Minimum Tolerable Pond Temperatures

[Pondmaster]

It was 10 degrees for the overnight low in Middle Tennessee a couple of days ago. My pond temperature was 36 degrees. It is distressing so I did some research and came up with this interesting article.

http://www.pondtrademag.com/articles/ar-73/

Here are a couple of excerpts from the above link:


"To make matters worse, there are articles warning that water colder than 39° F. can be lethal or at the very least, deform koi. Unfortunately, this kind of information is misleading and not factual..."

"In my own aerated 10,000-gal koi pond system that is 5.5´ deep the bottom temperature was just above 32° this past winter. I have checked my thermometers for accuracy and they are correct. All of my 38 large koi survived the winter in great shape. I have been using the same technique for the last 17 years and have always been successful."

Comments?

 

[JustJack]

That says basically the same thing as several other articles I read when we first moved here last winter and I was worried about the fish. I've read many times since then that as long as they can breathe and have rocks to hibernate under that they'll be fine.

Being in Florida, I don't have to deal with freezing temps for any length of time, but my pond did have a pretty hefty layer of ice on it last winter and on a sunny day, I could see all my little fishies out swimming around underneath it. My pond temp was 40 last week but we've had several freezes since then so I don't know what it got down to. I forgot to check it before it got sunny again.

 

[Shdwdrgn]

Being at high altitude, I've seen my pond get down to 29 degrees before it starts to freeze over. Never lost a fish to the cold, and I have comets, koi, and shubunkin. I have also heard many times over the years of people who did not dig their pond deep enough and let it freeze up solid -- and still had 50% of their goldfish survive! That's some pretty serious hibernation.

 

[CometKeith]

Pondmaster, nice article, but do you really think his bottom temperature was just over 32 degrees? I bet it was a little warmer than that. Everything I have read says that 38 degree water is the most dense and sinks to the bottom of the pond. I think fish would freeze at 32 degrees.

 

[n2ponds]

I'm in Southeast Missouri and had two cold nights one was 6 and the other was 9. Both of the next days only got into the low to mid 20's. I went out to my pond the afternoon of the night after the 9 and my goldfish were swimming around the pond. the cold didn't seem to affect them too much.

 

[Pondmaster]

Pondmaster, nice article, but do you really think his bottom temperature was just over 32 degrees? I bet it was a little warmer than that. Everything I have read says that 38 degree water is the most dense and sinks to the bottom of the pond. I think fish would freeze at 32 degrees.

Yes I think it's possible that it could have been 32, mine was 34 before I covered the pond in a panic. Moving water doesn't easily freeze, and if your using even an airstone you won't have stratification unless your pond is 6' deep or better.