Time: Late May, any year.

Call comes in from pond customer(s).

Customer says: “Hey my fish are fighting and it looks like Mr. Bubble may have fallen into my pond. The pond kinda smells a bit too…”

Pond Pro says: “Cool, congratulations!”

Have A Question For Mike? Ask the Expert


Why? Because its spawning time for koi and goldfish and the customer will soon have fish babies! So,

 congratulations!! … “It’s a fish!”

     A lot of times the spawning season in our backyard koi ponds is brought to our attention because of the conditions mentioned above. Most pond owners are pretty tuned into the changes in conditions and “seasons” that every year brings us and our ponds. One of those “seasons” in our ponds, is spawning season; which typically occurs during May through June. Of course, a bit earlier or a bit later, a bit longer or a bit shorter of a spawning season depending upon where you live. And the “rules” of spawning get broken all the time when sudden condition changes occur that may trigger our fish into spawning mode out of season.

If you are not familiar with what to look for, so you can witness a koi spawning, there are some easy to recognize signs any pond owner can see.

We all know that our koi and goldfish get along very nicely, without aggression or competitiveness toward each other. This type of behavior makes up the vast majority of behavior we expect to see with our fish. Then one day spawning season hits and our fish are at each others throats, or at least chasing each others tails. The pond is full of fast, aggressive and frantic activity. The fish are chasing each other around and around, jumping clear out of the water at times, and jamming themselves into skimmer boxes, there is frantic group activity along the shoreline rockwork and plantings.

We also have pretty consistent water quality conditions with nice clear water, and a clean pond surface just about all year. Then spawning season comes to town and we see that our water quality is different. It has gotten very murky, it seems to have a slick surface quality, and the surface of the pond is also very foamy and getting foamier. The skimmer box is packed with foam, and gives out a very fishy smell when you open it. What the what!!!

koi spawning new jersey

Our pond’s conditions change quickly, drastically, and it isn’t all that pretty but don’t panic. Its nature and the will to survive.  Don’t try to  “treat” the water to get your normal day to day conditions right back in your pond. Step away from the de-foaming agent you are about to dump in your pond! Put down the test kit. Try to let your pond go through the entire spawning without interference. Let your filters take care of the water quality, let them do their jobs, it may not happen overnight; but they’ll do it. Your water quality will rebound to normal daily conditions, of course assuming you have proper filtration.

The rotten fish behavior we witnessed with all that aggression and chasing will soon return back to its normal day to day slow dance of color within your peaceful pond. But koi are koi, and they are going to spawn how they see fit, and there is nothing we can do to change it, even though all the males gang up and beat up the females pretty badly. The aggressive behavior is definitely stressful, sometimes deadly, to the females and you will see they get pretty beat up with torn fins and all, sometimes bloody. However, they too will typically recuperate with a little time, and also return to normal day to day activity in the pond. The female koi may not talk to the male koi for a while, but time heals all.

The smelly water, you know that pondy smelling water; well that will dissipate as well and your pond will go back to (hopefully) it’s odor free state of being. If any smell lingers then carbon will due the trick to remove foul odors.

Some fun stuff to do during the spawn is to get some photos (yes, I realize how that sounds) or video (I know how that sounds too). When the koi and goldfish calm down, go try to see some of their eggs. Koi and goldfish eggs should be visible around the shoreline rocks and plants. The eggs will be clear, round, and the size of a grain of salt, maybe a tad larger. Try to hatch some eggs indoors in a small tank of pond water and gentle aeration; you’ll be surprised how easy it is!

After the “koi and goldfish courtship” is over, take a good look at your fish to see what condition they are in. Take measures if necessary. Make sure that they are being properly aerated, especially in very foamy conditions. A good pond aerator is always good to have on hand! After they have calmed down give a good rinse to filter pads they will be pretty nasty.

Just a few weeks you will likely start seeing darting little koi and goldfish fry around the edges of your pond; swimming in and out of the rockwork and plants where they will grow out until they are real deal baby fish. A short few months later, colorful little koi will be milling in with the bigger koi trying to get in on some of those delicious pellets being served up; and it will make you happy.

So, that is why the pond professional told the customer “congratulations” when the customer thought that their pond had gone completely off the deep end!

“Congratulations, … it’s a fish!”

Written by Mike Gannon

Mike Gannon

The LOVEYOURPOND Blog is written by Mike Gannon of Full Service Aquatics located in Summit, NJ. Mike is an award winning pond, water garden, and water feature builder. Always “In The Pursuit Of All Things Aquatic” Mike has been a lifelong hobbyist and providing professional services since 1995. Mike is the creator of The Pond Hunter video series seen on Youtube and has made several television appearances on Networks such as HGTV and the DIY Network. He also hosts the Pond Hunter Radio Broadcast, a show on everything aquatic, every other Wednesday at 8pm EST. You can see what else Mike is up to at the following sites:


    Comments Feed
  1. Mike Gannon Says:

    on November 17, 2018 at 2:02 pm

    Hey Seth. Thanks for reaching out. Yes you can buy koi in Colorado. I would suggest checking out local suppliers if you have any, OR buy them online directly from a koi breeder so you can get the best quality at a good price. Good luck and enjoy your koi pond!! -Mike

  2. seth Says:

    on November 16, 2018 at 8:54 pm

    – hi mike i am 12 years old and i am thinking about buy a koi. and i am wondering in colorado can you own a koi; if so do you know any good places to buy one do i grow them from a kin of a older one? thank you soooooo mutch for the info

  3. Marilyn Says:

    on September 11, 2018 at 4:07 pm

    My goldfish had babies…….are they supposed to be black?

  4. Mike Gannon Says:

    on September 9, 2018 at 3:16 pm

    Hello Lizzie! Something as simple as a temperature change could trigger a spawning event if they are truly spawning. I am very happy to hear how well your pond is doing! Thanks for reaching out from France! Bon chance et rester en contact!! -Mike

  5. Lizzie Ballantyne Says:

    on August 27, 2018 at 4:03 pm

    Hi Mike, thanks a million for your informative site and for all the answers to your readers’ questions. I have a pond that we made last winter. In the spring I added 11 goldfish and 13 mosquito fish. (I live in a hot part of the south of France and mosquitoes can be a real pain.) The pond is a huge success with thousands of bees and other insects visiting very day, along with some birds. 9 months on and I now have hundreds of tiny mosquito fish and my goldfish have produced at least 25 babies. I noticed today that they appear to be spawning again. Could this be because the temperature has just dropped from 38 degrees C to about 28 degrees? I’ve just taken off the shading net too. What has sparked a new spawn at this time of year?

  6. John Francis Says:

    on August 4, 2018 at 5:08 am

    Hi again Mike,
    Some 18 months or so after my first communication concerning koi breeding I can report that only two of the six fry I “rescued” survived. However, I recently had to replace the plastic containers I use for filtration and thought you and your readers might be interested in seeing my relatively simple design. Check out:

  7. Mike Gannon Says:

    on July 25, 2018 at 11:22 pm

    Hello Jennifer. Thanks for reaching out. Based on your description I would offer a guess that you have baby goldfish in your pond. Goldfish are born with a dark coloration and develop color as they grow. Koi are born with color already present. Good luck and enjoy the fun!! -Mike

  8. Jennifer L Armstrong Says:

    on July 24, 2018 at 3:12 pm

    Hi Mike! I have a koi pond with 3 new koi (I purchased in May) and 7 existing fish (may be koi, goldfish, comet….I’m not sure how to identify them). None of the existing have the ‘whiskers’ but 2 resemble koi. The other 5 look more like goldfish (maybe, I honestly have no idea). There are 30-40 baby fry swimming around my pond now. They hatched around july 4. They are all still brown. Is this common? Is there any way to tell what I have? I know its not a lot of info, but I am a rookie to this…..I was shocked to see all the babies!!!!

  9. Mike Gannon Says:

    on July 7, 2018 at 7:16 pm

    Hello Joe. Sorry to hear about the fish loss. Its hard for me to say why the fish have died since there are lots of possible reasons for fish to die, especially in spawning season. Females will typically die from stress and exhaustion since the males are relentless during spawning time. I wish I could give you a better answer but I’m missing information! Good luck. -Mike

  10. joe Nichols Says:

    on July 7, 2018 at 5:08 pm

    The last two times my Koi spawned, some of my fish died. The first time I lost 5. This time I lost 2. What is causing this. I had perfect conditions in the pond before the spawn. In both cases the female was one of the victims. What can I do to prevent this in the future?

  11. Mike Gannon Says:

    on July 7, 2018 at 7:19 pm

    Hello Denise. I would use an aerator that is not too strong. Try using a diffuser that will create very small air bubbles and does not put out too much pressure. Just gentle pressure! Have fun and best of luck!! -Mike

  12. Denise Hahn Says:

    on July 5, 2018 at 2:40 pm

    I am attempting to hatch my pond fish eggs in an indoor tank. What exactly do you mean by gentle aeration? Should I buy a new aquarium kit or just get a 5 gallon tank and an aerator? If so which one would you recommend? Thanks! Denise

  13. Mike Gannon Says:

    on July 2, 2018 at 4:00 pm

    Hi Judy. I’m glad my site is helpful!! I think a couple weeks after a spawn it is good to go ahead and run your vacuum. Enjoy! -Mike

  14. Judy Says:

    on July 2, 2018 at 4:05 am

    Hi Mike,
    Thank you for the very helpful site! We have a goldfish pond and were away for most of the spring. The pond is badly in need of cleaning, but the fish were happy enough to spawn anyway. How long after the spawn should we wait before vacuuming?

  15. Mike Gannon Says:

    on July 2, 2018 at 4:24 pm

    Hello Dave. Thanks for reaching out. In the world of fish, the goldfish and koi are probably the worst parental fish out there so the hiding is certainly not any protective measure by the fish. Good luck! -Mike

  16. Dave Coovert Says:

    on June 18, 2018 at 1:49 am

    We have 6 golfish of varying age and size. We added 3 to our four a couple months ago but one diied within a few days. There was a lot of activity and everyone was getting along pretty well and then they all seemed to disappear, but I would catch a glimpse occasionally of the larger two hiding under a large rock outcropping. Now I have seen a very small baby goldfish on the rdge of the rock a couple of times. Is this hiding behavior simply protecting the babies? Thanks ib advance for your help.

  17. Mike Gannon Says:

    on July 2, 2018 at 5:34 pm

    Hello Travis. It is a pretty common scenario when fish get spooked by a predator they will hide for days afterward. Give them time and they’ll come around again, they always do, they are very social creatures! Good luck. -Mike

  18. Travis Simpkins Says:

    on June 16, 2018 at 12:48 am

    Hey, I have a small pond in my backyard with 5 goldfish. I went to feed them the other day and could not see them anywhere. My wife and I thought someone stolen them or a predator ate them. Two days later I found them all hiding under the filter. They now hide there day and night where before they were very active in the pond. I thought maybe they laid eggs under the filter or could there be a predator visiting our pond at night? Any suggestions?

  19. Mike Gannon Says:

    on July 2, 2018 at 5:40 pm

    Hello Lesley. The concept of “too many fish” will vary from pond keeper to pond keeper and how the pond is being managed, filtered, etc. I can’t really answer with a number amount. To thin the population from time to time you may have to lower water level and physically remove them, or let nature take its course and the population will level out on its own with time. Enjoy!! -Mike

  20. Lesley Says:

    on June 12, 2018 at 11:41 am

    Hi Mike, We moved house last September and have now got a pond never had one before, 10 meters across approx 120,000 litres. spawning is happening how do you know if you have too many fish we have a selection of koi, goldfish and some others which I don”t know what they are. How do we thin them out if we need to

  21. Mike Gannon Says:

    on June 3, 2018 at 10:36 pm

    Hi Patti. You will have anywhere from between 2 weeks to 6 weeks of yelling at your husband to go out and check the fish! 😉 Enjoy! -Mike

  22. Patti Says:

    on May 31, 2018 at 8:25 pm

    Omg…the koi are going crazy. I yelled at my husband to go out and check on them. It seemed like they were attacking two of our thirteen fish. It was awful to watch the two swim around trying to get away. Okay now it makes sense. I guess I’ll have to put up with the loud noise and bubbly look. How many days does this go on for?

  23. Mike Gannon Says:

    on May 21, 2018 at 11:34 am

    Best of luck with this spawning. Keeping ammonia down while spawning is occurring is difficult but the use of small water changes is probably the best approach. I hope you get lots of little fish!! Enjoy. -Mike

  24. Carmen L Alvarado kovats Says:

    on May 13, 2018 at 5:19 pm

    Thank you so much for the quick response! I listened to the podcast and it was wonderful and full of such great information! I’m going to try to do just as she said with this batch of mops but still need to learn how to keep ammonia down for the future spawns when i keep the mops in the pond. We did a tiny water change yesterday and the ammonia again at night registered .50 . Went out again this am and the surface was covered again with foam that smelled too high heaven lol and tested 1.0. While it’s not lowered , it’s not the whopping 5.0 it started out at the initial spa spawn. Thank you so much for your wealth of knowledge and sharing it with us! Wish me luck!

  25. Mike Gannon Says:

    on May 12, 2018 at 11:34 am

    Hello Carmen. Thanks for reaching out and congrats on the spawn!! I would suggest a slow water change, possibly by way of dripping in fresh water, or pumping out small amounts and replacing with fresh water. this will lower the ammonia and keep it from spiking up. Here is my podcast where I talk with a guest on raising the eggs that may provide you with some more information. Take a listen!! Good luck. -Mike

  26. Carmen L Alvarado kovats Says:

    on May 12, 2018 at 2:17 am

    Made 7 spawn mops for the pond and we now have eggs! Unfortunately my ammonia spiked and was a whopping 2.0! Used ammolock and salt to prevent further damage to our koi and waited for our filter to weed out the ammonia. It would lower at night to. 50 then back up to 2.0 during the day. For fear of losing our koi we removed the mops with the eggs and transferred them to a 20 gallon tote and small filter. It seems to have worked and our ammonia level is down to .50 and still dissipating. I prefer your method of just letting naturer run its course, however not at the expense of mykoi. What can i do in the future Mike, without removing the breeding mops and allowing them to stay in the pond in regards to ammonia levels????

  27. Mike Gannon Says:

    on April 24, 2018 at 11:26 pm

    Hello Denise. If you are trying to raise them then I would suggest doing exactly that!! And then listen to this excellent podcast of mine on raising the eggs! Click the link.
    Good luck and enjoy! -Mike

  28. Denise H Says:

    on April 23, 2018 at 10:57 pm

    Hi should i take tje eggs out of the pond and put into a tank as soon as they are layed thank you

  29. Mike Gannon Says:

    on April 9, 2018 at 1:27 pm

    Hello Roy, thanks for the question. It is hard for me to say whether your fish could be dying or not but based on your description it does not sound to be doing very well so keep a close eye on it for any further developments, hopefully with improvement being the result. The eggs sound pretty big to be goldfish eggs, perhaps they are frog eggs? If you are interested in raising the fry then separating them out would be advisable, if you want to let nature run its course then leave them as they are and see what comes out from the spawn!! Enjoy! -Mike

  30. Roy Says:

    on April 5, 2018 at 2:59 pm

    We have a garden pond approx 7 x 4 x 4feet deep. We have gold fish about 20 various sizes about 3 years ago we noticed about 13 small black fish, who now are turning golden and maturing well.. Question one large goldfish appro 9 inches long and very fat, looks in distress and exhausted, we have found what look like eggs (fry) very small white peas with a black piece of rice inside, is the fish dieing? Should I separate the spawns into a smaller tank within the pond ?

  31. Mike Gannon Says:

    on April 3, 2018 at 12:29 am

    Hi Linda. Thanks for reaching out. I want you to listen to this podcast, it has lots of great suggestions that you’ll find very helpful. Good luck!! -Mike

  32. Linda Says:

    on March 31, 2018 at 9:40 pm

    We have a mixture of 1 Koi, shebunkins, comets, calicos, bullnose and goldfish. They are all thriving however, when they spawn in the plants it is a feeding frenzy and in 3 years time we have only had 5 babies. It is so disappointing and not sure if there is anything we can do???

  33. Mike Gannon Says:

    on April 3, 2018 at 12:38 am

    Hello Dee. It would seem kind of early for egg laying but stanger things have happened in our ponds! Yes, koi can fertilize the eggs and create a cross breed of koi/goldfish. Good luck! -Mike

  34. Dee Says:

    on March 8, 2018 at 11:29 am

    Hi i have a pond with one red comet and 2 koi. The red comet seems to have become really fat the past 3 days it has not come up to eat iether. Could it be laying eggs and if so can those eggs get fertilised by the koi?

  35. Mike Gannon Says:

    on January 3, 2018 at 2:59 pm

    Hello Ben. Congratulations on the spawn! If your tank now has elevated ammonia levels I would recommend at least a small water change to bring down ammonia faster. Your tank will eventually reduce ammonia on its own, but I’d give it a bit of help with a water change. I hope you hatch some beautiful babies!! You should listen to my podcast which discusses spawning tips. Here is the link: http://www.blogtalkradio.com/thepondhunter/2017/11/02/the-pond-hunter-radio-broadcast-ep53–how-to-raise-baby-koi-fish-from-eggs Good luck! Mike

  36. Ben Says:

    on January 3, 2018 at 5:31 am

    Hey mike, nice information you have here. I am from singapore.

    Currently housing 3 ranchu(lionhead) with 2 male and 1 female. Yesterday when i came back after work, noticed my whole tank murky with hundred or thousand of eggs everywhere in my 75gal tank. It almost cover the entire base area. I manage to retrieve some of the eggs from my plants and placed them in a shallow container treated with blue water and air pump for gentle aeration. Now my main tank which was cycled, now having ammonia is reading 0.5, nitrite 0.25, nitrate 5.0 ph 7.6. Will it return back to normal after spawning completed? Will there be possibility that the fry will hatch in the main tank? And how long it might actually takes. Thanks!!

  37. Mike Gannon Says:

    on December 16, 2017 at 10:21 pm

    Hello Zeena! Thanks for reaching out from Australia. It sounds like you are off to a good start with the provisions for small goldfish fry. Some rocks and plants are exactly what I would recommend to allow them to grow out a bit until they can take care of themselves. Good luck and enjoy! -Mike

  38. Zeena Wolstenholme Says:

    on December 13, 2017 at 12:49 pm

    Hey mike.. excellent info here… and u respond to all enquiries! I’m from Newstead victoria australia….

    ..I think our goldfish r up to shenanigans! And would like some advice on what to put in the water trough ..to help protect the babies to come?
    Yes..i said Water Trough.. for our sheep and alpacas.. no filter its gravity fed.. goldfish seem quite happy there! I’ve put a few rocks and ” holey bricks ” and bought 1 plant from aquarium…

  39. Mike Gannon Says:

    on October 14, 2017 at 11:44 am

    Hello Bonnie, thanks for reaching out. I’m not sure that there is anything you really need to do! The fish will take care of themselves. If your filtration is not adequate perhaps a couple of small water changes might be advisable, otherwise wait and see what type of baby fish you get!! Enjoy. -Mike

  40. Bonnie Doll Says:

    on October 14, 2017 at 11:32 am

    Hi, ok it seeems to me that my cois are busy with breeding activities. All signs are showing. Agressive actions, jumping out the water, chasing each other, foam on water and fishy smell. I have no plants, rocks or any structure in my pond. The pond is about 7000 litres. What shoul i do now? Please help me.

  41. Mike Gannon Says:

    on September 25, 2017 at 12:19 pm

    Thanks! I will. Mike

  42. Deangelo Says:

    on September 22, 2017 at 11:12 am

    I truly appreciate this article. Keep writing.

  43. Mike Gannon Says:

    on September 25, 2017 at 12:21 pm

    Hello Denise. Although you may lose a few eggs due to drifting downstream the majority of the eggs will likely stay where the fish lay them, so I still think you’d do pretty good. I’m happy to have you get all the updates!! -Mike

  44. Denise Woods Says:

    on September 21, 2017 at 4:39 pm

    Hi, I live in Owasso Oklahoma. We have a 500 gal (approx) rock pond with waterfall. The water runs into a large pond area that then flows to a creek and dry water bed to recirculate . Will the eggs of the koi float down stream? I have floating plants and water lettuce . I would love to have small fry but am worried they won’t survive . I would like to be but on your list for updates and information. Thank you

  45. Mike Gannon Says:

    on September 20, 2017 at 6:35 pm

    Very true Mogsie! Goldfish and koi are very fond of eating their own eggs!!

  46. Mogsie Says:

    on September 15, 2017 at 8:04 am

    Hi, you forgot to add the bit where you dont have any baby fish left as the adults have eaten them all! My sarasa goldfish spawn every year but if i want to keep some i have to remove and rear them in seperate tank.

  47. Mike Gannon Says:

    on September 4, 2017 at 3:09 pm

    Hello Cynthia. Its very hard to give any input as to why they may have died, spawning could possibly play a role, but hard to say without better info. A late spawn is not very unusual at all, I’ve seen it plenty of times. Have fun!! -Mike

  48. Cynthia Bozeman Says:

    on September 4, 2017 at 2:39 pm

    I am in Florida, and I have had 2 of my fish one a beautiful large goldfish and one large yellow koi die back to back for no obvious reason I can account for. They were 6 yrs old and have spawned once this year. I have monitored my water quality since the deaths 2 days ago and this morning I check them and they have spawned. I have never had them spawn in Sept! Is this strange so late in the year and now I wonder if getting ready to spawn had something to do with my 2 fish dying. They had no visible marking on them and looked perfect.

  49. Mike Gannon Says:

    on August 30, 2017 at 10:07 pm

    Hello Gwen. Yes you can definitely remove the eggs, place them in an aquarium that is filled with water from the pond, add some gentle aeration and soon enough you’ll have baby koi!! Have fun. Mike

  50. Gwen Gass Says:

    on August 27, 2017 at 11:59 pm

    Hi I just got my first pond about two months ago. As luck would have it there was a add free koi ,of course I was so excited ,we as in family and I went to get my first koi. The pond was all ready. We got four beautiful big koi. One white, one black, two yellow we could tell one of the yellow one was full of eggs. The white didn’t make it , the black one had jumped out and died. The very next day all the eggs had been layed. What a smell eggs everywhere. We did end up with two babies. My question is can you take out the eggs and put them in aquarium to hatch?

  51. Yang Zhang Says:

    on August 19, 2017 at 6:28 am

    I also heard that I should increase the breeding pond water temperature. Everyone tells their own experience, I don’t know which is correct.

  52. Mike Gannon Says:

    on August 27, 2017 at 8:40 pm

    Hello Yang. As much as I love koi, I am not really qualified to give you advice on how to manipulate their breeding patterns. I typically let mature run its course! Good luck. Mike

  53. Yang Zhang Says:

    on August 19, 2017 at 6:26 am

    Hi Mike, I am in Sydney Australia. I have a backyard pond about 13 x 10 x 6 feet, with few kois are about five years old. The spring is coming in about two months time. I never breed them before. (tried last late spring, no chasing)
    I had setup a breeding pond, the size is 3.5 x 3 x 3 feet.
    Should I put breeding male (or female) to the breeding pond first (one month before)? Or any thing to make them start chasing. thanks

  54. Mike Gannon Says:

    on August 27, 2017 at 8:38 pm

    Hey, sorry to hear that Bill.

  55. Bill Says:

    on August 7, 2017 at 8:40 am

    Hi mike its bill again don’t bother to reply to my last message as I have just found out what is wrong with the goldfish it has got dropsy and it’s far to late to treat it.

  56. Bill Says:

    on August 7, 2017 at 8:00 am

    Thanks for your reply but the size of the fish dose not seem to be normal the fish is still swimming and eating ok but it doesn’t look normal it looks more like a puffer fish then a goldfish is there anyway I can send you a picture of it for you to have a look at

  57. Mike Gannon Says:

    on August 27, 2017 at 8:37 pm

    Hi Traci. Yes, try to catch them if you’d like to tank raise them, otherwise just let them be. Most baby fish will probably need to be around a full inch or so before the bigger fish may ignore them as a possible snack. – Mike

  58. Traci Says:

    on August 6, 2017 at 2:07 am

    Hi …I have many very small fry swimming & darting in the pond where I have very large koi. Should I catch the babies from the pond or net the big ones off? How big do fry have to get before they won’t be eaten?

  59. Mike Gannon Says:

    on August 2, 2017 at 8:45 pm

    Hi Bill. If the “bigger” growth seems to be of a normal nature and it is not a unilateral growth then I would not be too worried. I have witnessed some pretty significant differences in growth rates among fish that are from the same spawn even. Good luck, Mike

  60. Bill Says:

    on July 29, 2017 at 12:04 pm

    I have got 7 goldfish in my pond I noticed one of my fish is just getting bigger it’s been like that for about 2 months it is now almost the end of July it seems to be swimming okay I just want to know if there is anything wrong with the fish as i have read that the organs of the fish can keep growing thank

  61. Mike Gannon Says:

    on June 29, 2017 at 10:58 am

    Hello Mary. Thanks for reaching out. As you have witnessed, goldfish are very hardy creatures. At 18″ deep in your pond I would be a little worried every year but it seems they are doing just fine! During winter months the fish go into torpor which is similar to hibernation. Your pond is just deep enough apparently to let them do that, but many other factors come into play for your specific situation. Mike

  62. Mary Hoogr Says:

    on June 26, 2017 at 12:59 pm

    My pond is 8X12 about 1 1/2 ft deep. Live in Minnesota where temps drop to-35 or more in winter. I leave the goldfish in the pond, no heater, and the pond freezes over. Come spring they all there swimming around. How can they live?

  63. Mike Gannon Says:

    on June 29, 2017 at 11:05 am

    Hello Bern. Yes they will progress on their own just fine for a while. Once they are fry you could offer them some pulverized fish flakes as a starter food, and adjust the feeding as they grow. They grow quick. Have fun!! Mike

  64. Bern Says:

    on June 13, 2017 at 11:52 am

    Hi Mike,
    great site and great info. have seperated the eggs from obvious places and placed them in a huge water bottle bottle (5 ltrs). Have put a couple of pieces of oxenagating weed in and a little of the vegetation they were trapped in. Can introduce gentle airation.
    Is it just wait and see, or do I need to introduce any nourishment. quite happy to grind up some “egg and chips” if that is their fancy but seriously will they progress initially without any extra help from me, and if so, for how long.

  65. Mike Gannon Says:

    on June 4, 2017 at 5:05 pm

    Hi Stephanie. I’m curious why you say she is pregnant! There really is not anything to do for the fish, they will handle it all! If she is pregnant and ready to spawn you will probably see some of the other fish chasing her around the pond, this is normal, but can be stressful to the fish; especially when it is a new comer to the pond, so keep an eye on her during the first few days. Have fun! -Mike

  66. Stephanie Kraft Says:

    on June 2, 2017 at 3:22 pm

    Hi I bought a fantail goldfish yesterday and I am almost positive she is pregnant.. we have her in our pond with a few other koi and goldfish do I need to do anything special for her.. I’m new to this.. pls help

  67. Mike Gannon Says:

    on May 31, 2017 at 12:28 pm

    Hello Jennifer. I’d love to visit Scotland sometime! Yes, everyone eats the eggs including the koi and goldfish. It sounds like you have a good amount of stock for your pond, especially as they grow to full size and reproduce. Enjoy! -Mike

  68. Jennifer Says:

    on May 31, 2017 at 11:39 am

    Hi Mike – thanks for all the info I have found on the above. I live in Scotland and have Koi for the first time – my pond is approx 7,000 gallons and we are going through a spawning session – think both Koi and comets. As I have already several hundred toadlets – will they eat the eggs. I notice a big drop in egg numbers overnight ? Also how many fish could a pond this size support – at the mo – 7 x 18″ koi, 11 ass comets / goldfish, 2 blue orf and 2 tench – who I think took care of the tadpoles, one orf died – put it down to sampling toadlets – thanks again for a site with lots of info – Jen

  69. Mike Gannon Says:

    on May 30, 2017 at 11:02 pm

    Hello Paul. It won’t be long!! It seems males are pretty generous about sharing their sperm and generally ready to go at it. I am not actually sure how old a koi would be before being too old to reproduce, but my guess would be about 10 years. Have fun! -Mike

  70. paul sittmann Says:

    on May 29, 2017 at 7:26 am

    I have two 8 inch female koi bulging with eggs and one male koi in my san diego pond, the females and male are darting around chasing one another…how many days will this go on before the female releases her eggs and the male fertilizes them to complete the spawning process is??? Is the male koi always ready with sperm? is there an age when the male would not have sperm? thanks so much I can not wait!

  71. Mike Gannon Says:

    on May 30, 2017 at 11:10 pm

    Hello Terrie. Rubbing on rocks etc. would typically be more of a way for fish to try and remove parasites from their skin. Maybe eggs, but I’m not very sure about that. Good luck! -Mike

  72. Terrie Says:

    on May 18, 2017 at 5:38 pm

    Hi. Im new to koi and ponds and im loving it i have a 11ft bu 10ft pond 3 and half foot deep. At the deepest point it has 4 shelves or leveles. My kio and gold fish are getting amazing i have 10 gold and 7 koi all get along swimmingly. Its a natural pond with a pump. I have frogs that have moved in too. Some of my fish keep rubbing themselves on the rocks and the base. Do you think they may have eggs?? Thank you reading. Amazing blog by the way.

  73. Melijahbleu Says:

    on May 5, 2017 at 6:30 am

    Hello, we had ducks in our pond and bought 10 feeder gold fish to see if the ducks liked them. They didn’t ????. That was last summer. Now we have …. Umh maybe 150 mixed colored gold fish. Not sure what to do now, but I have been feeding the fish since the water temp reached 50 degrees. My husband’s now laughs cause I chase the ducks out of the pond so they don’t eat the fish.

  74. Mike Gannon Says:

    on May 30, 2017 at 10:43 pm

    Hello Laura,
    Koi can carry their eggs for some time before releasing them. Spawning season is soon! Have fun! -Mike

  75. Laura Martinez Says:

    on April 24, 2017 at 6:42 pm

    Hi Mike!
    How long does the female koi carry the eggs? It has been a couple weeks now, that my female koi has been very fat.At least that is what I am assuming it is. This koi is very fat all of a sudden. Thought the spawning would start by now. I have had babies before, but never really noticed the fat female first. Thank you.

  76. Mike Gannon Says:

    on April 19, 2017 at 3:17 pm

    Once the eggs are scattered and fertilized it will only be a matter of a week or so before tiny fry emerge. The growth rate after that is unpredictable but it should be safe to say that within a couple weeks or so you should be able to spot small fish. Good luck. -Mike

  77. hazel gisbourne Says:

    on April 12, 2017 at 11:27 am

    April 10th 2017. our 16.000ltr pond with waterfall has six gold fish. today they appeared to be doing the mating rituals, if they have ‘been at it’ what is the gestation period please?

  78. Mike Gannon Says:

    on April 3, 2017 at 12:43 pm

    Hello Jules, thanks for reaching out! Unfortunately without really seeing what’s happening I can only guess, but it does sound alot like spawning behavior. Another good indicator will be foaminess on the surface of the water, and/or some smell coming from the pond. If you see some of these accompanying conditions then it is very likely a spawn has occurred. Good luck!! -Mike

  79. Jules DeBaecke Says:

    on April 1, 2017 at 3:33 pm

    We have a small (400+) gallon pond with a waterfall. Almost every year we have one or two new babies, both goldfish and koi. This month, for the first time we saw the koi consistently huddling around a plant near the water surface which is probably the warmest part of the pond. From what I have read in your comments, my guess this has to do with the spawning process. However, we have never seen this congregating since we created the pond almost 10 years ago. Do you have any other words of wisdom?
    Jules DeBaecke

  80. Mike Gannon Says:

    on March 15, 2017 at 9:41 pm

    Hey Lauren. Glad to see you are researching how to keep care of your koi! Feeding koi, when to start and when to stop, is dictated by the water temperatures. Every are will have a slightly different feeding period, of course warmer southern areas may not stop feeding at all. Here is a link to a podcast I made covering how to feed your fish, please check it out:
    Also, lots of other info, right here in the LOVEYOURPOND blog!
    Good luck, Mike

  81. Lauren McC Says:

    on March 10, 2017 at 4:42 pm

    Hi I have moved into my new house in November and the previous owner has left the pond full of Koi Carp!
    I have researched a little and understand not to feed them through the cold months and they have been at the bottom and haven’t needed to worry much!
    As of today they are all swimming around and coming up to the top of the pond – does this mean I need to start feeding them? Please help any information I’m very grateful as I would love to look after them correctly!
    Thank you! Lauren

  82. Mike Gannon Says:

    on March 9, 2017 at 12:56 pm

    Hi Stephen, thanks for reaching out. I’m happy to hear that your fish are spawning and doing what happy fish should be doing. When using the spawning mops/mats or whatever material you choose to use for the collection of eggs, you will want to actually remove the mat from the pond to allow the eggs to grow out into fry, etc. If you leave it in the pond, the eggs will likely get picked at but hopefully many of them will be protected enough to not lose all of them. If possible, gently remove the spawning mat, fill a tank with pond water, add aeration, and you will have lots of baby fish very soon!! Good luck! -Mike

  83. Stephen B. Says:

    on March 2, 2017 at 9:03 pm

    Hi Mike, I have 150 gallon Rubbermaid stock tank pond on my patio with 3 mature(apx. 5-6 inches) and 5 young(1-1.5 inch) common goldfish. Earlier in the spring i noticed them showing spawning behavior and quickly made some DIY spawn mops. Unfortunately i missed them that morning and for whatever reason i never saw any fry as a result of that spawn. However, i left the mops in just in case because i had spotted a single egg, and i hoped there could be more.(or more to come) Then this week I saw them frolicking again and i checked the mops which are now LOADED with eggs. I am really excited but also concerned because I’ve read that goldfish are notorious for eating their young. Obviously with only 150 gallons of pond I cant care for them all if they all survived anyways so I’m okay with some losses as long as a few make it. Will some of the fry reach adulthood if everyone is left in the pond together? Or are my adult goldies going to tear it up like hungry orcas? Please advise.

  84. Mike Gannon Says:

    on February 13, 2017 at 10:21 pm

    Hey Michelle, sounds like a lot of fun happening in your pond! Good luck! -Mike

  85. Michelle Says:

    on February 13, 2017 at 9:58 pm

    I live in Florida and have a small front door pond. I came out to see my small goldfish being pushed around and beat up and looking like she couldn’t breathe. I freaked out and did a 50% water change after noticing it was foaming and murky and oily looking. After the water was out, I noticed these tiny eggs all over. That’s when I researched and found that my goldfish of a year were spawning! I felt like an idiot! ( and probably looked like one too!) Now I am hoping the eggs will hatch with all of my meddling!

  86. Mike Gannon Says:

    on February 8, 2017 at 12:24 am

    Hello Azlena, from all that you described it does sound like a spawn may have occurred! Please let us know the results. Good luck – Mike

  87. Azlena Aliyah Says:

    on February 2, 2017 at 6:32 pm

    Hello Mike,
    I live in Orlando, Florida and I think I have some comet goldfish fry in my backyard pond. Generally, I would go outside to see the pond everyday but lately,I had been busy and hadn’t seen it for about 3 days. I came back and the water did smell a bit fishy and I saw little fry looking things. I also saw some black dots on plants that were submerged in the water. Also, I see that the adult comets seem kind of isolated, under the waterfall and not swimming around/being as energetic in a school as they used to. Do you think my comet gold fish may have spawned?

  88. Mike Gannon Says:

    on December 24, 2016 at 2:09 am

    Hello John. Thanks for the interesting account of your pond. It is good to know how some pond keepers need to think on their feet and resolve issues without the use of the neighborhood aquatic center! Apparently your fish are very happy with their environment even though it may not be ideal to our eyes! The egg yolk is usually used for new born fry, but you can grind some flake for slightly larger fry and move them onto whole flake food very quickly. Once they are a bit bigger you will want to use a pellet food if any is available. As far as the nipping of the fins I am not surprised to hear this. Koi will do much better with the classic goldfish, but the more ornamental varieties goldfish are very delicate. Any goldfish that is highly specialized with protruding eyes, bubble eyes, unusual body shapes and fin configurations should be reserved for aquarium keeping. Classic goldfish and shubunkins tend to do best with koi. Keep me up to date on your pond!! -Mike

  89. John Francis Says:

    on December 20, 2016 at 1:36 am

    After all that, I forgot to ask the question! Food for the fry – I am currently grinding regular fish food (the red and green floaters) to a fine dust and using that, but I have been told that the yellow of a hard boiled egg can be used. Do you have any advice/alternatives?
    Thanks in advance

  90. John Francis Says:

    on December 19, 2016 at 10:50 am

    Hii Mike – great site and info, thanks for that
    I am a British ex-pat living in the Philippines.. I have a small garden pond, roughly 8 by 5 feet, and this is my first year of keeping koi. Originally I had koi and goldfish (triple-tailed and bubble-eye) but the goldfish were steadily dieing and it wasnt until I was down to the last four (of ten) that I realised that the koi were fin-nipping and stressing out the goldfish!
    However, that was a side-issue as I was fighting a losing battle against green algae badly colouring the water. I eventually resolved it by having semi-floating pennywort in the two large water-feature bowls and making my own filters out of used fine-nylon fishing net of all things, which works a treat! Being “in the provinces” in the Philippines there is no handy aquatic centre to visit.
    Eventually the pennywort was so dense that it blocked the pouring lip and water was coming over the edges of the bowls. .You can see how prolific it was at the start of this short video: https://www.youtube.com/watch?v=o7aRiB3AACw
    So, I dumped all the pennywort, except for a couple of strands, into the pond, and to my great surprise this happened a week later:
    Yes, they were spawning. As i have no other place to keep extra fish I just let nature take its course and subsequently I spotted a couple of fry hiding in the pennywort. I checked every day until i was surprised yet again – one fry had travelled through the pump (eeek) and had ended up in the bowl (you can just see it in the centre of the bowl:
    It could just have easily ended up in the filter and I wouldnt have even known. So, to stop that happening again I managed to net the remaining fry (all six of them) and they are all now safely in the bowl.
    Sorry if this is a bit long, hopefully other keepers will find this interesting.

  91. Mike Gannon Says:

    on November 7, 2016 at 6:09 pm

    Hello Janice. Your fish should have not problem carrying the eggs during winter months, but they may also “reabsorb” the eggs during those months. -Mike

  92. Janice Novak Says:

    on November 6, 2016 at 7:01 pm

    Hi Mike,
    I have a female comet carrying eggs, I live in the Albany NY area so it is getting cold fast, will she carry eggs through the winter? or will she lose them due to the cold?

  93. Mike Gannon Says:

    on November 7, 2016 at 5:53 pm

    Hello Steve. I do think you can use coir material to help protect the eggs. Goldfish will eat just as many, or more, of the eggs as the koi will. All the koi will likely spawn at the same time, but the ones that don’t may spawn later this year since they can spawn more than 1X/year. Good luck!! Mike

  94. Titan Uranus Says:

    on October 17, 2016 at 1:21 am

    Hi Mike, from estern Australia (Think California climate). We’re in spring now, southern hemisphere (down under)and all. Cold in winter, baking hot and dry in summer…
    We got about 8000 litres, sand filter with zeolite & 2 Olive barrels with jap matting, waterfall and aerator. Added extension this past year, and sand filter, which requires plenty maintenance, (I put matting in leaf collector now). We’ve lost a lot of fish in past few years, just up and die on us. Now with extension and better filtration, impeccably clear water, still algae on the sides. Have plants above the watefall for filtration. Haven’t lost a fish in over a year!
    We have about 25 Koi now, some small, a few mid size, and 1 big breeder we bought. Mix of male and female. We got showas which are < 1 year old bout 250cm which are obviously gravid. An some Hariwakis, and some others, my mrs knows what they are, basically we've paired them all up…
    Now they are near spawning, I think it's gunner be a free for all?
    Are they likely to all spawn at the same time, the big 'cow' and the young maidens?
    I thought young koi, like their first year weren't viable as breeders?
    I can seperate the ponds, and isolate the breeding pairs, if they don't all go off at the same time??
    We have a goldfish pond, seperate, flows into koi pond, planning putting eggs/fry in there, an hopefuly GF won't eat as many as the Koi will? The Koi just smash them…
    Bit worried over some of the smaller females, specially the showas we paid top dollar for, the males are a bit larger, hoping they wont gang rape them and leave them for dead…
    We have petty much smooth sides, rendered, painted concrete with alage, which they chew (salad). Is there any cheap substitutes for laying mats? I know the Koi shop will have some, at a price, but what about Coir mats or similar? So long as they not treated with chemicals… We can then transfer to smaller pond….
    Cheers steve

  95. Mike Gannon Says:

    on September 2, 2016 at 3:56 pm

    That is a great suggestion Rebecca. The livestock trough heaters can throw off some pretty good heat! -Mike

  96. Rebecca Says:

    on September 1, 2016 at 7:31 pm

    PS – I have a comment for Shirley… We live in Helena, MT and we use a floating heater like the ones they use in horse throghs to keep their drinking water from freezing. We put that in the pond when it starts getting cold and they always survive and they hibernate in the pond. You can buy them pretty inexpensive at murdochs. 😉 Want some more koi?

  97. Mike Gannon Says:

    on September 2, 2016 at 3:55 pm

    Hi Rebecca! thanks for reaching out. I would always try to find a local koi dealer or fish dealer and see if you can trade the babies for supplies, etc. Of course you could give them away too and help spread this amazing hobby to others! -Mike

  98. Rebecca Says:

    on September 1, 2016 at 7:27 pm

    Hi Mike,
    What do we do with all the koi babies? It looks like there are about 30. We have about 11 full size koi, and our pond isn’t big enough for over 40 fish when those babies grow up?


  99. Mike Gannon Says:

    on August 31, 2016 at 11:35 pm

    Hi Shirley, congrats on the baby fish! I would say that your area has some extremely temperatures; in my area I am warning customers about temperatures in the single digits, so to have to deal with -30 to -40 degrees is a whole different thing! I would be concerned with only 2.5ft depths when dealing with negative temperature conditions, I think I would play it safe and bring in the fish for the winter months. -Mike

  100. Shirley Says:

    on August 28, 2016 at 10:28 pm

    Hi Mike
    Well just like everyone we have noticed little baby fish swimming around our little Koi pond which is about 600 gallons and about 2-2 1/2 feet deep. We live in Butte, Montana and have always taken our Koi inside for the winter. We would drain the pond for season. Now we have tried to catch the babies but they are very very fast! Is it wise to just leave the water in the pond for the winter as well as the fish?? We do not want to loose the babies but are new at this. What should we do. Our temperatures get to a low of -30 degrees and sometimes -40. Help

  101. Mike Gannon Says:

    on August 31, 2016 at 11:32 pm

    Hello Mark, koi can spawn from 1 – 3 times per season! Enjoy the NEW babies!! -Mike

  102. B.A. Marks Says:

    on August 26, 2016 at 7:28 pm

    I have 3 different size babies today the newest batch?? How many times a season do they have babies???
    Thank you

  103. Giovanni Carlo Says:

    on August 23, 2016 at 3:45 pm

    Welcome Mike,
    That is what I do to breed my kois, but I only kept the beautiful ones and sale the pet quality to petshop and reseller.

  104. Mike Gannon Says:

    on August 23, 2016 at 11:32 am

    Thanks Giovanni, this is a good strategy for maximum fry to be raised! -Mike

  105. Giovanni Carlo Says:

    on August 20, 2016 at 6:01 am

    I think it is best to breed your koi in a breeding tank so that you have more baby kois to survive parent koi breeders eat their eggs after spawning, so if you breed them in breeding tanks, you can take them after spawning.

  106. Mike Gannon Says:

    on August 17, 2016 at 11:32 am

    Hi Pat, if your pond is deep enough they can stay out all winter, no problem! -Mike

  107. Pat Says:

    on August 15, 2016 at 8:50 pm

    Hi Mike! I just read your article about spawning Koi and goldfish…really enjoyed it! I noticed ‘babies’ swimming around a few weeks ago and now I’m a very concerned parent!:-) So far all looks good…everyone is getting along, but now I am worried about what to do in the Fall! My pond is under 2 feet at its deepest…only had 4, 5-inch goldfish for about 4 years and so it was easy for me to bring the goldfish in every winter. Now I’ve got these little guys to contend with. Do you think they could be left out for their first winter or do you think I should bring them in as well…separate aquarium?

  108. Mike Gannon Says:

    on July 28, 2016 at 6:23 pm

    Hi Cam, if the spawn was a couple of weeks ago there may not be eggs still, but if so, then sure why not collect and try to hatch a few of them! Good luck!! -Mike

  109. Cam Says:

    on July 27, 2016 at 2:46 pm

    Hi, Mike. Glad to have found this site! I have a small pond (350 gal.) and right now 8 goldfish live in it. I have a fountain and small waterfall for aeration. A few years ago I had a lot of string algae, and when I went to remove it there were some fry in it (very exciting) so I put it back. This year I finally got a UV filter, as have had a lot of green water the past few years and the water really cleared up. I noticed some string algae coming back. I left it alone, hoping for more babies. Notices some to the aggressive spawning behavior a few weeks ago. My question is, should I remove as much of the algae as I can to a tote at this time, hoping it contains eggs?

  110. Mike Gannon Says:

    on July 18, 2016 at 12:11 pm

    Hello Ott, your pond sounds nice! It is possible that you are removing some eggs when you take out dead plant material, but I would not think that it is enough to make any major impact. -Mike

  111. Ott Gangl Says:

    on July 16, 2016 at 10:29 pm

    Hello Mike, my pond is 25ftx14ftx32 inches (avg) deep, I have it for at least ten years and there are about 50 goldfish in it, predators get some now and then so the occupant numbers vary. There are six or seven waterlilies and a lotus in pots and at this time cover at least 60 percent of the surface. 6-10 are blooming all the time and with the ones done and sunk and the the leaves deteriorating I go in and take out the leaves and done lilies. I notices spawning behavior but no small fry. My worry is that when removing quite a bit of the lily leaves and stems, am I also removing the eggs which may be attached to them? I clean about once a month.

  112. Mike Gannon Says:

    on July 11, 2016 at 8:42 pm

    Hi Trish, thanks for reaching out. The golden rule is 1 koi per 1000 gallons; however most people do not go by the golden rule. The real question is how well your pond is filtered, if you have great filtration you can have a higher stock level. I have a 2500 gallon pond and keep about 19 koi in my pond and they all seem to do very well. -Mike

  113. Trish Says:

    on July 11, 2016 at 6:44 pm

    Hi Mike,
    Thanks for all the great information. We installed a 3500 gal pond 4 years ago. My Koi were given to me, I have about 20 and the largest are at least 24″. What is a general rule of thumb for fish to water/ ratio?

  114. Mike Gannon Says:

    on July 11, 2016 at 8:52 pm

    Hi Patricia, I’m so glad you find my site! The lack of spawning could be for many different reasons and is hard for me to say exactly. The size of your pond may not have alot to do with it, although it may be a minor contributing factor. Hope you stick around. -Mike

  115. Patricia DiCarlo Says:

    on July 8, 2016 at 9:27 pm

    Our pond is small by comparison to some of your posts. We have had it for almost 20 years. In the winter, we put a small screened puptent over it with heater and bubbler (we live in Maryland and even with some heavy snowfalls, it has always survived.) A few years ago we lost most of our fish to a great blue heron(they are really big and we live close to the Patuxent River, so we now keep netting on the pond year round) We have four goldfish and seven fairly large koi. I think one of the goldfish mated with a koi because it is orange with striated black markings on its head. It is the smallest member of the pond and I try to make sure it gets some pond sticks when I feed them every day, but I think with this exception, our fish are mostly celibate (LOL) because I have never witnessed anything resembling spawning. Is it because the pond is fairly small (a few hundred gallons with a nice equally small waterfall?) I have given some to people with an enormous pond and one small white koi, whom I felt was blind because he always swam around the food, but never seemed to ingest it. He did not survive, sadly.
    Sorry for the long post, but this is the first time I have ventured on to a site like this.

  116. Mike Gannon Says:

    on July 5, 2016 at 9:39 pm

    Hey Gary. Congrats on the baby koi, they are always fun to have. It’s hard to say if they are hybrid, you do have enough koi in there to likely have a male and female, so I would tend to lean toward them just being koi. You also have goldfish, there is always the chance that you have both type of baby in your pond, koi and goldfish babies. I don’t know if I’d assume anything just yet, I think its good to just give them a little more time to develop and you will know who’s who in a couple of weeks! -Mike

  117. Gary Says:

    on July 3, 2016 at 5:00 pm

    Three years ago I increased my pond size from 135 gls to 750. I have 3 Sarassa goldfish and another 6 Koi. I added another Koi that must be a female because we have had babies the last two years. For the most part the babies are all black with some white or yellow on the heads and perhaps down its back. Since I’m certain that the last Koi added is the Mother, are all of these fish hybrids? Should I assume that they aren’t going to develop the colors that all of the other Koi have? I can’t check for the “whiskers” yet unless I catch one (which isn’t that easy). We do have a beautiful koi that is black and white and we are hoping that they will turn out like that but the more I read the less hopeful I get. Any help you could provide would be appreciated.

  118. Mike Gannon Says:

    on July 5, 2016 at 9:34 pm

    Hi Jackie. It’s a fair assumption that the koi being chased is the female. Spawning for female koi is not safe at all even under best of circumstances. Female koi can and do become injured and exhausted. But that is how nature has designed their spawning and there is not much we can do to change that behavior. After spawning time is over, they will all go back to living together peacefully. Some koi keepers do choose to keep male koi only or female koi only ponds, so that is an option if you want to avoid the stressful spawning time every year. 500 gallons is on the small side for the stock level you are keeping, many of us are guilty of overstocking. From time to time I suggest giving some away and getting back to a base stock level. They may very well fill the pond up again with more babies and then you can give some more away a few years from now. Enjoy! -Mike

  119. Jackie Says:

    on June 29, 2016 at 2:09 am

    Hi Mike, thanks so much for all the helpful information! My husband and I recently acquired a number of koi from friend of ours who is selling her house and planning on filling in the koi pond. We ended up with 5 large koi, ranging from about 12″ – 24″ long, and 6 smaller koi about 8″ inches in length. The morning after we introduced these fish into our pond which only had about 15 very small koi in it, we noticed foam all over the top. After reading your article and watching the fish in the pond, it was clear that they were spawning. What I noticed is that there were 3 of the 5 large koi all following and bumping the smallest of the large koi, who I assume is the female. I’m not sure what gender the last and largest koi is as it didn’t seem to be in on any of the action. I’m concerned about having so many male koi with only one female. Is it safe for her, or do we need to remove some of the male koi? Also, I believe our pond is only about 500 gallons. We did not originally intend on keeping all the koi in our pond as we didn’t think it would be big enough for the number and size of all the fish. Should we be looking for a new home for some of our new fishy friends or is there enough room for all of them in our pond? Thanks for your help!

  120. Mike Gannon Says:

    on July 5, 2016 at 9:27 pm

    Hi Janet, I think that yes you could be right. Given the conditions you describe and the time of year, spawning is a great possibility! Good luck! -Mike

  121. janet morgan Says:

    on June 28, 2016 at 8:43 pm

    Hi Ive got a mixture of koi and goldfish in a large pond approx 2.5mtr x 4mtr x 4..5ft deep, got told that was around 10000ltr??. Over the past couple of weeks I noticed they weren’t really interested in eating and a fishy smell as described above, I thought oh cant wait for new pump and filter to arrive! (After replacing pump and filter on Friday.) Yesterday around my plants and sides of the pond i noticed white foaming, not a large amount. but quite a bit! I studied aquaculture but specialised in shellfish farming. I am right in thinking they have spawned?

  122. Mike Gannon Says:

    on July 5, 2016 at 9:25 pm

    Hey Cyndi, congrats on the baby koi! From what I understand, koi are borm with their basic color base and the patterns and other colors develop quickly and as small fish they will have a visible pattern. Their pattern can still develop over time until it is fully “fixed” when the pattern has reached a point that it will not change much if properly cared for. -Mike

  123. Cyndi Says:

    on June 26, 2016 at 2:12 pm

    Mike we have 25 koi we have had our pond for 8 years this year we got lucky noted spawning I removed plants after we have babies… My question is they are one month old and a few of them have some visible black but the rest are completely white or cream it was a flock spawn when will I see color in them or will they stay whitish cream?

  124. Mike Gannon Says:

    on June 23, 2016 at 9:02 pm

    Hey Grant, The fry need to eat. Use a pulverized koi or goldfish food. Finely crushed flake food, or finely crushed pellets; the powder at the bottom of a food container is also good to use. They will accept this type of “powdered” food and grow fast!! Good luck and have fun! -Mike

  125. Grant Says:

    on June 23, 2016 at 11:42 am

    Mike (Nice article!) if I want to raise some fry in an aquarium I’m guessing they can survive without food for a while, but how long can they last & what should I feed them eventually?

    Regards Grant.

  126. Mike Gannon Says:

    on June 18, 2016 at 11:51 am

    Hello Kay. Congrats on your new fish! I don’t think they were attacking your koi. Right now is spawning time and alot of koi and goldfish are ready to lay their eggs. If goldfish sense that a female koi is going to lay eggs they will chase her in the hope of getting some of the eggs to eat! I think that is what you are seeing. they won’t actually attack each other but it can still be pretty stressful for the fish being chased. I think it was ok to take out the offenders until they are ready to calm down a bit, but they can go back in pretty soon. -Mike

  127. Kay Says:

    on June 18, 2016 at 6:34 am

    I had 8 goldfish in my pond already. The pond is about 12′ X 12′” & 3-4′ deep. I introduced 4 Koi fish today. About 4 of the goldfish were chasing a Koi at any given time & the Koi looked like they were getting cornered & then the goldfish appeared to be nibbling at the Koi. The Koi were getting chased all around the pond & it seemed like they were getting bullied, & harassed by the goldfish. The Koi were having to swim pretty fast & at other times they would try to hid under some of the cave areas, or back up to a rock. My daughter & I took 2 of the largest goldfish out of the pond, leaving 6 smaller ones with the koi. Is this the proper thing to do & what was going on with the fish in our pond? Would they kill the Koi?

  128. Mike Gannon Says:

    on June 17, 2016 at 1:03 pm

    Hi Steve. sounds like a romantic pond you got there! I would be inclined to just let nature takes its course, its what they do, and it probably is not the first time. It can be hard for us to watch because we are used to the “tranquil” beauty of our fish, but how they spawn is how they spawn and they will be just fine. Good luck! -Mike

  129. Steve Says:

    on June 17, 2016 at 10:27 am

    A really useful post, thanks Mike! I ‘inherited’ a pond with a number of different fish (koi, gold, tench I think) when I purchased a new house earlier in the year.

    I just went out to feed them this morning, and one of them is being chased quite vehemently and flipping up out of the water quite a bit.

    We’re going to keep a regular check on her, and if needed move her to a large plastic box (unfortunately I don’t have another pond or tank!) with current pond water if she gets too tired, or would you recommend we just let nature take it’s course? She is probably 18″ and isn’t even the biggest in there!

  130. Mike Gannon Says:

    on June 17, 2016 at 1:12 pm

    Hi Campie. It will be pretty likely that you will find eggs in your filter. I’d try to clean it soon before they start to decompose. I like the hiding spot you provided for your fish! -Mike

  131. Campie Says:

    on June 16, 2016 at 12:14 pm

    Mike, have had my 300 gal pond for over 10 yrs. See the fish are spawning now. Have also notice they don’t eat much during this time. My biggest fear is when i clean the filters will there be eggs in there? Have an alge pump also which keeps things pretty clear. was wondering why my filter was turned upside down the fish flipped it it is a good size.
    Something that may help others i have a large black plastic pot sideways from a plant bought. Already has holes in bottom put a rock in it. The fish love it hide there in the winter and also way from prey, think it help with warmth when they are altogether.

  132. Mike Gannon Says:

    on June 17, 2016 at 1:13 pm

    Hi Jan. Spawning behavior can last for days. Female koi can lay eggs up to 3X per year. -Mike

  133. Jan Says:

    on June 15, 2016 at 8:55 pm

    Hi Mike can you please tell me how many times will one Koi spawn ? Does it happen over a number of days or hours etc ? It is just once every year ? My Koi seem to have been spawning for days ??

  134. Mike Gannon Says:

    on June 17, 2016 at 1:24 pm

    Hi Paul. Nice choice on goldfish! I love the lionheads. It certainly could be spawning behavior, it kind of sounds like it is but is hard for me to say for sure, but the murky water, aggression, and I’ll bet when you open the top of the tank you get a good smelly wiff of “goldfish love” too. Probably spawning. -Mike

  135. Paul Says:

    on June 11, 2016 at 9:48 am

    Hi Mike I have a 40 litre fish tank with 4 lion head gold fish.
    Have noticed the water becoming very murky there was a bit of aggression over the one fish at one point and now this particular fish continues to lay still on the floor of the tank and every now and then swims quickly to the surface and settles back down on the floor. The other fish are now quite sedate and swim around normally. Is this a sign of spawning?

  136. Mike Gannon Says:

    on June 17, 2016 at 1:31 pm

    Hey Cindy! How fun to be raising those little fry!! I would not wait to introduce them to the 30 gallon tank and leave the little guys in the 5 gallon to grow up a bit more. Once spawning begins the female will release her eggs within a pretty short time span, but exactly when is hard to tell and I do think I’d let nature take its course. I’m pretty happy to see 6 or 7 successful babies after a spawn even though the potential for many many more is there, but that is just me, others may want to raise as many as possible!! Good luck and congrats! -Mike

  137. Cindy van Laar Says:

    on June 10, 2016 at 11:48 pm

    Hello Mike,
    We are on our second batch of fry this season, two different large ponds. I noticed one of our females is expecting and the guys are ready for action. Multi-tier bio filtered ponds n both locations…we managed to save 159 (yes, we counted) fry from first spawn and they are growing nicely in 5 gallon aquarium. It is like having a new baby or a puppy, for sure. This week we found koi that hatched on their own in pond. They are three times as large as our aquarium fry. Question: when do we introduce them to 30 gallon intermediate tank? We will separate tiny ones to remain in 5 gallon until they are large enough to avoid demise from larger fry. Size matters. Last question: once spawn dating commences, when can we expect our female to deliver the goods? We happened to be at the right place, right time, last spawning event. Just let nature take her course and let those who are adept at hiding make their way to adulthood?

  138. Mike Gannon Says:

    on June 17, 2016 at 1:34 pm

    Hey Mike, that is awesome! It must be easy to lose time when witnessing one of natures incredible treats of hatching fish. Enjoy it! -Mike

  139. Mike knight Says:

    on June 10, 2016 at 9:10 pm

    Day 4/5 I have hundreds and I mean hundreds of tiny fry in the pond and also in the holding tank where I placed a select few plants that were covered with eggs along with more eggs hatching as we speak it’s so fun to watch I’m losing hours without realising it. I no most if not all the fry within the pond will more than likely get eaten by my bigger fish but nature will prevail that’s why I’m glad I could remove some of my plants that got covered as I can grow some on and share the joy with others once they become of a reasonable size but that’s about a year from now just in time to get going again next year if they decide to keep their spawning activity up. Now time to do my big clean within my main pond to get it looking good again now they have finished having their fun and the fry have hatched 🙂

  140. Mike Gannon Says:

    on June 17, 2016 at 1:37 pm

    Hi Gerry. Yes, koi will eat their own eggs and tiny fry. There are many things you can do including adding things to your pond like plants, or artificial spawning mats, to capture the eggs which can easily be transferred and hatched in a small aquarium tank. how much you want to protect them is a personal choice, you may have more babies on your hands than you know what to do with!! Good luck and enjoy! -Mike

  141. Gerry Says:

    on June 8, 2016 at 11:45 am

    Hi Mike, My koi did have babies but they vanished, Do they ever eat their young and is there anything I should be doing to protect them? Thanks.

  142. Mike Gannon Says:

    on June 17, 2016 at 1:39 pm

    Hi Mike, I think what your doing is perfect. Yes, the filter is too strong and will suck up eggs. -Mike

  143. Mike knight Says:

    on June 7, 2016 at 6:46 pm

    Day 2 after my koi acting erratically and all around the edge of my pond plus over my plants and rocks I find tons of eggs literally hundreds even thousands of them I moved a few of my plants into a separate container as they have the most eggs over them I filled it with water from my pond and put a bubble blower in their to keep water movement so it doesn’t stagnate is there anything els I have to do to the plants in the container for the eggs to hatch safely or is that sufficient enough as I wasn’t sure to add a filter or not as I thought that could suck up the eggs with to much water movement even suck up all or any fry that hatch I do have it covered over tho so nothing can get to the plants within the container any advise you could give me to see them through would be much appreciated thanks

  144. Mike Gannon Says:

    on June 17, 2016 at 1:59 pm

    Hey Mike. I think it is safe to say that spawning is happening! You got all the classic signs. -Mike

  145. Mike knight Says:

    on June 6, 2016 at 9:30 pm

    My partner called me up at work to tell me we have an intruder all new plants were floating around the pond and the fish seemed to be very agitated all chasing each other around particularly my 2 larger koi was being chased around even to the point where they were leaping out of the water like a dolphin playing by the time I arrived home after my wife put all new plants back where we put them with some extra rocks around them to keep them as marginal rather than bottom of the pond plants and to my surprise the pond is going frothy and skimmer/waterfall filter is starting to smell really fishy I no its not dirty as only done a clean out 2 weeks ago and weather has been overcast with light rain since so no blazing sun to blame could all this relate to spawning.

  146. Mike Gannon Says:

    on June 17, 2016 at 2:10 pm

    Hello Guy. I don’t think I’d use any soap solution if it is being sprayed by your pond. On a side not, the bees getting water are probably not any type of bee that would attack or sting if you just let them collect their water. -Mike

  147. Guy Gillespie Says:

    on June 4, 2016 at 3:18 pm

    I have a 700 gallon cement pond with a waterfall, right lol and africanized need by the thousands. Can I spray the bees getting water with a soap and water mixture without harming my koi? The koi are spawning now.

  148. Mike Gannon Says:

    on June 2, 2016 at 3:12 am

    Congratulations Keith! I’m glad to help, how can I help you? -Mike

  149. keith marston Says:

    on May 29, 2016 at 9:07 pm

    my gold fish has just layed egg this is my first time so can u help me please k marston

  150. Mike Gannon Says:

    on June 2, 2016 at 3:14 am

    Hello Vernon, yes there is the possibility that they may lay eggs. Make sure to make them happy and give them nice water quality and they will likely have some babies!! -Mike

  151. Vernon Says:

    on May 27, 2016 at 7:46 pm

    Hi when we bought the house 6 months ago,one of the reasons is it like koi.i have about 60 full grown koi,5lbs to 10 lbs..is there any possibilities that this koi would lay eggs?

  152. Lois Says:

    on May 25, 2016 at 7:45 pm

    Thanks very much, Mike. This answers several questions from the last several years that I did not even think to ask before. I have about 8 goldfish in a fifty gallon stock tank on the deck along with a bunch of Japanese iris which bloom. Only one of the goldfish is from last year because the raccoon got the others. I have a stock tank heater and a filter system which loops the water down a cement pan back into the pond. Everybody has been getting along fine until suddenly one is chasing one other relentlessly. I will wait to see what happens next. Several years ago I did have one fish jump the whole way off the deck to the yard below. Then one other year I had what I now understand were eggs. I will be patient this year and let nature do it nature’s way. Thanks.

  153. Mike Gannon Says:

    on May 27, 2016 at 2:02 am

    Hi Rhoda. First thing is to stop giving them wine and lighting candles by the pond… Maybe the only real way to slow production is to attempt to sex the fish and remove either the males or females, and that is a big task. Otherwise I’d just let nature run its course and thin the school from time to time. -Mike

  154. Rhoda Minard Says:

    on May 21, 2016 at 8:36 pm

    How do I slow the reproduction of fish in my pond, I just cleared out 150 fish and still have about 60, HELP Do I have to do this every year? I have 2 joining ponds with about 6000 gallon of water between them Last year I threw about that many away also. I started with 3 Koi 10 shubunken and 10 comets.

  155. Mike Gannon Says:

    on May 27, 2016 at 1:59 am

    Hello Rea. Koi can start to spawn at a pretty young age and the size may not play much of a role in that. The sexes can be told apart in a couple of ways, one of which most hobbyists will never attempt, so I like to go by sight. Typically the females are much more full bodied, while the males retain more of a slender “torpedo” shape. -Mike

  156. Rea Mingeva Says:

    on May 20, 2016 at 3:42 pm

    Your comments on the smelly pond signifying breeding time is so informative and we are newbies at the koi scene. We have a spring fed pond about five thousand gallons, in Tennessee. The pond sits at the end of a draw where the water heads out to a cliff/waterfall which drops 40 ft into the valley below. Our largest koi is about 4″ long. There were two, but on seems to have disappeared, maybe into a cave (?) We introduced three of them this spring. Two questions: how mature/age/size do koi have to be to breed. Is there a way of knowing if you have both male and female. Thank you. Rea

  157. Mike Gannon Says:

    on May 14, 2016 at 1:29 pm

    Hi Amanda, during spawning time it is pretty common for the females to become exhausted and kind of catatonic! -Mike

  158. Amanda Says:

    on May 9, 2016 at 5:07 pm

    Thank you for this info. Had a pond over 10 years and never seen this activity. I was pretty worried about 1 fish beaching itself in the weed then getting good trapped beaten bitten poked etc by another one and then sandwiched between two fish literally squashing it. I now know it’s a lady fish being attacked by the bad guys. Is it usual for lady fish to be catatonic like state for a while?

  159. Jim Says:

    on April 12, 2016 at 11:30 pm

    Good info here… Was doing research as to why one of my goldfish had flipped out of the pond and died. The day before I had cleaned out the coy pond due to the change in water color and smell, about 25% of the water was removed. I have a built in ground coy pond, approx. 300 gals. I didn’t realize that it was mating season. Anyway, because of the smell and water unclarity along with all of the activity with the fish brushing against each other and playing around . I was not aware of what was going on ( mating season). Today, I when to feed my fish and one of them had jumped out and died. This explains what had happened… The aggressive behavior during the mating process explains why one of the goldfish had been playing while mating and had jumped out of the pond (not by choice) For the future, I will lower the water level during the mating season to avoid anymore miss-haps like this.

  160. Mike Gannon Says:

    on April 14, 2016 at 12:24 am

    Hey Trish, thanks for sharing your story! good luck and keep in touch!! -Mike

  161. Trish Cole Adams Says:

    on April 12, 2016 at 1:49 pm

    I live in Winnipeg, Manitoba… I have a small backyard pond with 7 koi, I previously brought my koi inside for the winter as are temperatures can be very severe, they are now 5 years old and are very large as well as the rank becomes very smelly, so decided to try to keep them in the pond with a continious pump and pond decider, well I’m exstatic they have all survived. In Winnipeg we also gave the danger of wild animals eg. Raccoons, I have a bridge over the pond that they seem to have been able to out smart the animals so dark. I’m excited to watch for spawning, eggs and babies. Thank you for sharing your information, looking forward to more.

  162. Mike Gannon Says:

    on January 29, 2016 at 8:22 pm

    You have to develop an eye for what is called body conformity. Once you understand what their bodies should look like, it becomes easy to spot a koi that is loaded with eggs!! They are fat!! Mike

  163. petie Says:

    on August 28, 2015 at 10:48 am

    how do you know if a koi is full of eggs?

  164. Mike Gannon Says:

    on August 11, 2015 at 12:49 pm

    Hi Elizabeth. I think spawning activity may necessitate a water change depending on how your system is filtered and a few other variables. However if you are changing the water try to give the water a little time before changing so you are not altering water chemistry too fast too soon! Congrats on the spawn! -Mike

  165. Elizabeth Says:

    on July 26, 2015 at 2:56 pm

    Large Koi spawned…should the pond have a small percent of water change?

  166. Elizabeth Says:

    on July 26, 2015 at 2:53 pm

    Hi I was so thrilled when after having my Koi pond professionally tested with perfect results I came out to feed the Koi in my pond only to see foam as if someone put soap in the pond I know that the Large Koi spawned…should I do a water change ? or wait?thanks Dale….Elizabeth

  167. Mike Gannon Says:

    on August 11, 2015 at 1:04 pm

    Hi Kesha! A bowl may be too small to get babies. They may spawn, but babies may not happen, but who knows! If the water is cloudy or a bit smelly do a small change of water. Good luck! -Mike

  168. Kesha Says:

    on June 30, 2015 at 12:38 am

    I have a glass bowl of five gold fish n the water suddenly got blurred and it was just changed yesterday. The water smells fishy and I don’t have a filter in that bowl cause I change it every week. I only have an air pump and don’t know if I should change the water. I want baby fishes!!! Advise plss

  169. Dale Says:

    on June 2, 2015 at 1:04 am

    Pls add me to your site. Thank you love the info

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