Winter Fish Kill – How To Prevent It

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Unless you happen to like temperatures way below zero, or blizzard conditions, you’ll probably agree that this past winter has been one to hate. It was tough on everyone, and everything, including fish.

There have been numerous reports throughout our area, and most of the northern U.S. about fish kills and large die-offs in ponds. In one case, a local pond lost around 9,000 pounds of fish. In the end, it created one big mess.

So what’s the solution?

Well, apart from having any kind of influence on Mother Nature, which we do not, the best option is to put some safeguards into place that can minimize the loss during the winter months.

The problem for fish in cold weather is that, if the water freezes solid, no fresh air can get into the water, and maybe more importantly, gases that accumulate from bottom sludge degradation, can get trapped under the ice. With no way out, or in, this combination can cause some problems for fish. Of course fish face other stressors during the winter, but when you see massive die off, it’s the air exchange that was most likely the problem.

So the solution is simple.

You use either aeration, and by this I mean a subsurface aerator that releases bubbled air up from the bottom, usually in one single, shallow position, or your use a surface based circulator, to keep a spot of ice open all winter long.

In a smaller pond, a pond heater would work well to for this purpose.

Basically anything that keeps a spot of ice open on the surface (and it doesn’t have to be all that big) will help with this exchange of air and gas build up. With a system like this in place you may still see a few fish die off in the winter, but generally you won’t see large fish losses in winter, or summer months when things get really hot.

Pond aeration in any form will therefore work as a great protective tool for your pond and your fish, all year round.

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