No Frozen Fish – How To Keep Your Fish Happy Over The Winter

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Perhaps more than any other fall pond topic, the questions that surround fish and cold weather management would likely come out to top them all.

Keeping your fish in great shape over the winter isn’t very hard once you have a few basics to work with.

This week’s video is an oldie but a goodie on how to care for your fish throughout the fall and winter months.

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P.S. Be sure to ignore the first 30 seconds or so where I talk about snow…:( Ick.

Got a fall and winter fish tip to share? Please do that below in the comments section…and thank you!

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15 thoughts on “No Frozen Fish – How To Keep Your Fish Happy Over The Winter”

  1. Great information Mark, I have only over wintered one year now, everything went well, the fish made it through to spring. I started feeding them Cherio’s once the water was close to 50 degrees, then by December I stopped feeding them. My only mistake was taking the net off too soon, and a hungry Heron stopped in an at all my fish except for one. I added a dozen goldfish, and what to my surprise a new fry hatched soon after. I now have approximately 26 4″ to 6″ fish. My pond is just a little over 4,000 gallons. Do you suggest I purge some of the fish before winter, or is the number of fish and the size of my pond safe?

  2. The video information is accurate and I simply use a heater during the winter(Northern Ohio) and remove as much matter from the pond and the fish do extremely well. Oh, I also make sure to clear the snow fall off the ice on the pond so sun light can penetrate. My pond is roughly 2,800 gallons.

  3. Hi,

    I have a 3,000 gallon pond with 10 large Koi. The fish are seven to nine years old and I have a couple of breeding females.

    Last year I removed all of the goldfish and drained the pond, removing all of the fish. That was the first time in nine years that I have done that. I normally just drain the pond down and removed the dead organic matter in the spring. We have severely cold winters, it sometimes gets down to minus 20.

    I leave my stream and pump running all winter, as the birds and I enjoy the stream so much. I had to use a deicer once but it cost so much to operate that I just keep a hole open with a pump.

    The biggest things I have found to maintain good fish health are.

    1. Trim all of the plants in the fall and remove any organic matter that you can. I found that Pondclear (bacteria) really worked for me this year.

    2. Salt pond in the spring. I put 90 lbs of kiln dried salt in for 22 days. (30 lbs per 1,000 gal). Usually around early March. That kills the parasites and puts a nice slime coat on the fish.

    3. I feed my fish cheerrios in the fall and spring then mix with the good stuff for the summer.



  4. Hi Robert,
    You should be just fine with your current fish load, as goldies don’t need as much room as koi do.

    Keep up the good work!


  5. I have a very small pond, 350 gallons. and overwinter fish year after year. I keep the filter and pump running, no fountain. Works fine, but I have trouble keeping the frogs around, any ideas? We are located in northern Ohio on Lake Erie.

  6. I have a 2200 gallon pond with 17 koi, largest being 9 inches. I clean out the debris before ever winter and my fish have made it through 6 successful winters with no problems. I have lilly pads and othter plant life which dies off every winter. I live in Southern California, so our winters may dip into the freezing temps for a short time. My question is: How often should the pond be completely mucked out? (if at all) I have heard some people say every year, others every other year, and others say not at all because it damages your ecosystem.?? I welcome your input.

  7. I live in the Sacramento (CA) area and my pond is very small – only about 120 gals. We don’t get nearly as cold in the winter as you do, but we do experience occasional freezing temps during the night. I keep the pump, filter and waterfall running year ’round. I’m curious if the tips regarding feeding are still relevant in this part of the country. Do goldfish metabolisms slow down in the winter months even in moderate temperature conditions?

  8. I have a 10000 gallon pond and keep approx 45 gold and Koi. I have only lost fish after the ice goes out [20 inches of ice]. I keep a heater and a air pump running all winter. Does anyone know why I would lose fish about two weeks after the ice goes out??

  9. I inherited a small pond of koi a year ago when I moved into a new house. Its about 8×5 and about two feet deep. I don’t know how many gallon of water.What is the most number of fish that I should have in this pond?
    Do I turn off the pumps and water fall for the winter. It can get very Cold in Maryland and we had over 36 inched of snow at one time last year.
    Thank you


  11. Thanks Mark, I have learned so much from you. I live in Saskatchewan Canada and it quiet often hits -30 or lower and I leave my fish in the pond with a floating stalk tank heater. The fish that I have lost, they seem to get caught around the edge in the stones,so this year and let me know what you think,I am going to drop my water level a little to try to prevent this.
    Thanks Mark keep up the good work.


  12. Looks like I got behind here…sorry:)

    Pat, I’m not sure what to tell you. We haven’t had any shortage of frogs here and like everything habitat would be the key. Find out what that is and provide it and you should have some frogs hang around.

    Hi Tommy, I think every pond will be different in how fast this stuff accumulates at the bottom. Any muck thats organic will help algae grow…that’s one thing we focus on so it’s good to get it out regularly if you can. By not letting it build up too much it makes the job easier. I personally don’t find any problem with removing it as necessary, it won’t hurt the pond if you have a good biofilter/system going.

    Hi Marianne, yes, all fish will slow down as the weather cools. Around 45 to 50 degrees you want to stop feeding for the most part and you’ll see them slow down alot as you go below that.

    Hi Yaz, to get gallons take length x width x depth in feet and multiply this number by 7.5 and you’ll have the estimated gallons.

    Hi Don, I’m not opposed to the idea of lowering the water as long as you don’t get too shallow…even with a heater I like to see a couple of feet in the pond at least more that two feet for sure.

  13. Hi dnunweiler,

    I saved your question for last because I think it’s safe to say there is no single issue as to why this might be happening. It could be a lot of things. Be sure to check water quality at that time…ammonia levels, etc to be sure that the biological activity is kicking in a long with the feeding start up. Usually though, when water quality is bad more than one fish get’s affected.

    If water quality is good, a lot can come back to stress issues (lots of changes in the spring). If it’s females you’re losing there might be reproductive problems.

    If no apparent physical issues are observed before the fish die, and you happen to experience this routinely every spring I would do a search of an experienced koi vet, either in your area or online and see what they have to say.

    All the best,

  14. Hello Mark, I have a small fish pond and I have a bad problem with algae. I have tried several things including commercial products. I provide plenty of shade but I cannot keep the algae away. What can I do to get rid of pea green water?

    One other thing: I have a water lily that puts out a lot of foliage but no blooms. What do I need to do to see some blooms?

    Thanks Mark

  15. Hi Allen,
    In terms of green water you can provide more surface coverage, but if the pond get’s a good bit of shade then you may want to focus more on nutrient reduction. Make sure your fish aren’t over populated for the pond’s size and your biofilter (if you have one) is working correctly and primed with bacteria. If all of this checks out ok, then look at a uv light as an add on as this might help specifically with green water.

    On the lily you may want to divide it as that can help them bloom better. Also provide a bit of fertilization directly in the pot and this should help it along.

    All the best,

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