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Harsh Winter Fish Kill?


I have received more questions like this one below this year than ever before and asked Aquascape Tech for their response.

Frozen turtleQuestion:

“I lost a lot of koi this winter because of extreme cold conditions, thought I had enough aeration and de-icers apparently not  would like alot more info on how to prepare better for harsh conditions”

Aquascape Tech Answer:

“Hhmmm that is kinda of hard to answer with no information from that person. 

I think the best response is that this was an extremely unusual winter and the even the Department of Natural Resources has issued a statement that they are expecting to see large fish losses in natural stream and lakes due to this year’s extreme weather.  Aquascape will be reviewing their winterization suggestions, but sufficient aeration, and openings in the ice usually work.  When you have the 3rd harshest winter in 150yrs (Chicago) it is difficult to predict all possible scenarios.  

Low stocking levels and having healthy fish heading into winter is also beneficial.  If the fish are stressed going into the winter months they are even less able to handle a severe winter.”

The PondMeister’s Normal Answer:

“The fish are fine in freezing weather. It is not the cold that kills the fish – it is the gasses trapped by a frozen over pond that kills the fish.

The 3 ways to keep a hole in the ice are: 

1.            De-icer – These keep a hole in the ice allowing the gasses to escape

2.            Pond Aerator – A pump which sits outside the pond and pumps air into the water. The bubbles keep a hole in the ice

3.            Submersible Pump at Water Level – The bubbling effect of the water keeps a hole in the ice. 

In extreme winter areas, some people chose to select 2 or 3 of the above in case one method fails.

Of course once the water temperature drops below 55 degrees there is no longer any need to feed the fish as their digestive systems are unable to digest the food.”

Frozen pond


I thought Aquascape’s response was a great answer and illustrates that even if we take every precaution, sometimes our best efforts may not be rewarded.

Nature can be BRUTAL!

date Posted on: Wednesday, March 19th, 2014 at 4:31 pm
Category Pond News.
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