Let pond freeze over or not?

[tayana]

My pond is about 3500 gallons. Sunday the temp was 36, this morning when I got up it was 32.  The air pump that I have running was keeping the pond open.  Tonight when I got home from work the temp was still 32.  My husband shut down some of the air flow into the pond.  Now about 3/4 of the pond is freezing. Is that what I need to do is let the pond freeze so it will stay warmer in the pond?  It is now 14 degrees outside!

[Kittyzee]

Most ponds up north freeze over except where you keep a bubbler or water moving.  The fish kind of go into 'sleepy mode' during the winter and hang out near the bottom.  They don't start moving around again until the water warms up.  Your pond should do fine as long as there is a hole open for air/gas exchange.   

[tayana]

I guess I wasn't very clear about where the 36 and 32 degrees was.  That was the temp in the pond.  I have been doing a lot of searching to try and find out just how cold the fish can withstand.  Seems not every one agrees.  I know by having a bubbler that my pond won't completely freeze.  Letting it operate normally I had no ice at all on the pond.  I was thinking that by turning down the bubbler and allowing the pond to partially freeze that it would keep it warmer for the fish.

[SueSTx]

In February last winter, I had about 10" of ice on my 18" lily tanks.  I did not lose any fish due to the cold.  Some days it was just too cold to melt a hole in the ice, but for most parts there was some air movement.

[Reedman]

As long as you keep a hole in the ice, the rest of the pond can (and will!) freeze over for months. 

Our winters here in southcentral PA are not quite as harsh as yours.  The water flowing off of my trickle tower keeps a hole in the ice most of the time.  When it gets in the teens, I turn on the floating stock tank deicer.

[Michiponder]

The type of fish, depth of pond, fish load, and amount of organics left in the pond can all make a big difference.   Especially up here in the North (I am in a cold area too.  MI).  32F sounds ppretty low.  Was that at the surface or down aqt the bottom?  Usually it is recomended in cold areas like ours to just keep a small area open and the deep water calm and slow so the resting fish can do just that-rest!  Speaking from experience koi do not fair well when chilled below 38F and are made to swim against currents.  Can you post more info?

Mikel

[tayana]

Most of my pond is 3 1/2 ft. deep.  I drained about 5-6 inches out of the pond when I shut down the waterfall to prevent water going back into my skimmer. I have 2 fantail goldfish about 9 inches, 2 koi 7 inches, 1 koi 6 inches and 1 koi 5 inches. Since I started my pond up in July I didn't have to many plants.  The couple that I had I moved downstairs for the winter. The air pump I'm using I purchased from Foster and Smith.  Its called an air pump 40 and I use a 7 inch diffuser with it.  My fish lay on the bottom anywhere from 7 to 10 ft. from the diffuser.  I don't believe they are getting much current at all.  I bought another thermometer tonight and put it on the bottom to try and get a reading.  It was hard to read it cause the minute you pulled it out the temp started to drop and it had small numbers.  I still believe that it is somewhere around 32-34 degrees.  I need to find a thermometer with big numbers.  The outside temp right now is a balmy 11 degrees.

[Waterbug]

I know this is against common wisdom but I'll put it out there...

An iced over pond will be warmer than one kept open with water movement. An iced over pond is about the only time a pond will stratify. The temp just under the ice will be say 32F while at the bottom, hopefully, 39F. Water movement would cause the entire pond to be uniform in temp, probably close to 32F.

Only pure water freezes at 32F. Most ponds have some natural salt from whatever water source is used. So with water movement you could get the water temp below 32F and still be ice free.

Gas exchange, yes, in a perfect world there would be great gas exchange. Trading low temp for gas exchange imo might not be a good deal. And the smaller the hole the less the gas exchange, so how much benefit is actually being seen would be debatable. But like Michiponder said, it depends on the pond. We're talking about the absolute limit of life here. Things can go either way and it's hard to predict which is going to be the best choice for a given winter.

My ice experience comes from upstate NY. Only a memory now.

[Julles]

Dear God, thank you for planting me in south TEXAS!   

I have to bow to the experts in cold areas on this one, as our ponds and pumps run all year, and the fish swim most of that time.

Just be sure you don't use a pump, because that would circulate the water, causing all of it to be the same, very cold, temperature.

[Michiponder]

Sounds like you have a light fish load which is a good thing.  If your organic load (leaves, plants, waste material) is also low you should not need to have much more than a small hole open for gas exchange.  Your bubbler should be placed on a shallow ledge to facilitate this.  Another thing you might consider doing is to install a small check valve in the air line to prevent water from backing up the line and freezing during a power interuption.  They are usually only a few dollars at a pet shop.  I have not had much luck with fantails at temps below the mid 40's for long periods like we have this far north.  Koi like it no less than the high 30's for our long winters.  Often fish kept below these temps sicken and die later in the spring.  Why did you lower you pond?  I just let my skimmer freeze for the winter.  The added depth would actually help in such a cold climat.  Wish I lived in a warmer area.  Gets real old not being able to see or feed my fish for four or more months.  Hope yours do OK and everything makes it through the spring.

Mikel

[finnpond]

    FYI... 

Fish, lilies, etc., made it OK through all this...  I did keep Sequence pump going, so both waterfalls were functioning as were Savio skimmer and DIY Skippy-type filters...



Take care,
Dave

[reddad35]

My pond is 5500 gallons. 5.5 foot deep at its deepest. I leave my bubbler going full strength but shut down the pumps and falls. I have a heavy koi fish load. Mine lay on the bottom. The pond freezes over but the is a hole in the ice from the bubbler.  Last year I added hot water to open a hole because it was too cold for the bubbler to keep it open.   

The first year I did not have a bubbler and I lost 6 koi.

I guess each pond is different.

[Esther]

Not only is each pond different but each year can be different. I've had mine 10 years now, and it's been so long since I measured, I don't remember for sure, maybe 13' X 10' X 24"-30" deep. I'm in Michigan so it gets cold but not as cold as some states. Maybe have a total of 12 fish with about 5-6 8" Koi and the rest nice sized mutt goldies. I have always shut the waterfall down when I see ice forming on the edges of it so as not to have any water blockage and drain the pond. Well I do have a float on the pump so that wouldn't happen anyway. So all I've ever done each fall is trim the water plants. Sink them to the bottom. Keep the leaves out as well as I can. And put in a DIY deicer for the winter. Every year but one, it was fine. Even if the deicer light went out and allowed the water to freeze. We used a blow torch to open it up, hoping none of the fish would come near. LOL. Oh I did mention an exception didn't I? That year I lost every one of my big Koi. I'm talking 24" and 4 lbs for the two biggest. They all died and I had to wait until the ice thawed to get them out. SICK!!! We still don't know what was different about that year. Maybe the fish had gotten too large for what oxygen was there that year. I have never cared a whit about the winter temp of the water because I'm too cheap to try to raise the temp with heaters and heard a long time ago about not circulating the water, especially the low water. I figure that the fish survive in the river down the road and the lakes. Yes I do realize my tiny bit of water doesn't compare to the river and lakes but the temps must be close.

Take a look at some of the tutorial and DIY subforums. You'll find some good information there that might help. The scariest part of the winter thing is the first couple of winters.

[Kittyzee]

I'm posting this question on this thread, not to hijack, but it may help someone with the same questions as tayana's.  My question is:  if you turn off your pump (submersible), what do you do with it?  Do you leave it in the pond?  And in running an airstone:  how do you solve the problem of where to put it?  It's not supposed to be in the wet and cold, so how do you solve that problem?

DH and I were wondering about these things since we thought about shutting off our pump for the first year ever.  We've never had any problems in shutting off the waterfall and rerouting the water back into the pond but wondered about shutting the pump down altogether, and running a bubbler.

[tayana]

I took my submersible pump out, cleaned it and put it downstairs. As for the air pump that is suppling air to my pond I bought a plastic container to put it in to keep it dry.  My husband put holes in it to run the cord and air tubing. He also put two three inch holes at the each end and put pvc elbows in to help  with air circulation.  So far its working pretty good.
Three days ago I had 13 inches of snow on my deck and now its gone.  We went from as low as 9 degrees to now it being 45 degrees.  The pond had ice on three quarters of it and it is also gone.  I can see my fish again and all 6 of them seem to be doing fine.  The water temp is reading 38 degrees.