Koi/Goldfish pond winterization

[LD1]

Anyone else out there in northern climates have goldfish/koi ponds? And if so, what do you do about winterization?

At my old house, I dug a ~10x20 pond that was ~4' deep. And approx 3000 gallons. I had one of them 1200gph fountain pumps right in the middle that set on the bottom and had a riser to the surface for the fountain head.

Leaving it run for the first winter killed all the fish. I though I was doing them good keeping the hole in the ice, but it turns out circulating THAT much water off the bottom of the pond.....and continual circulation of that bottom water and the whole pond gets cold. Like 33-34 degrees. And turns out that goldfish cant survive that. They like ~38-40 degree water in the bottom that is warmed by the ground.

So after that first winter, I choked that pump back to just enough of a trickle to keep a hole in the ice. Maybe 1 gallon a minute or so. Restocked with more dime-a-piece walmart goldfish and those fish lived another 5 happy years and got to be 8"-10" fish.

Fast forward to today, I have moved. Back in may I dug another ornamental pond. Bigger this time. Approx 20x50, 5-5.5' deep, and about 14000-15000 gallons. (based on the number of hours it took to fill with a 6GPM well and 7GPM city water tap).

This time I have a 3600GPH pump but no fountain. It feeds just a waterfall. But it does NOT pull water from the bottom. Rather from a shelf ~2' down.

the bottom is flat and ~4' wide x 3' high to the shelf x ~30-40' long. So there is a good 3000 gallons + water well below where the pump is. And the pump is at the end where the waterfall is as well.

Pictures of what the pond looks like.





And this picture shows what you cannot see now that their is water in there. It shows the wide flat bottom and the shelf to the left. That shelf to the left is where the pump is, up in the corner where the waterfall is. The pump is in the bottom in the pic just cause I was testing it out to see if 3600GPH was gonna be enough water movement for the sound I wanted.



So now that you can see the layout, and how the pump and fountain are situated in the pond and at what depth.......what would you do for winterization that will allow my ~50 or so ~3" goldfish to survive a central ohio winter?

Would you just leave things as is, expecting that the water where the fish will hibernate wont be disturbed and will maintain a warm enough temp from the ground?

Or would you pull the pump out and put in a de-icer? And if so, what type? Their seems to be two popular ones for koi-ponds. There are the thermostat ones with a 300w-500w element. Then there are the ones that only have a ~40w element and a small pump that circulates a little water from deeper in the pond.

Obviously I would just like to leave it as is and just keep an eye out for ice dams and draining my pond.

What say the masses on this situation?

 

[RNeumann]

I’d shut the pump off and just do a little bubbler. The fish aren’t bears but they aren’t exactly Flipper in the winter either. As the temps cool the fish slow and so should the water movement.

 

[LD1]

I’d shut the pump off and just do a little bubbler. The fish aren’t bears but they aren’t exactly Flipper in the winter either. As the temps cool the fish slow and so should the water movement.

You think the current waterfall and surface movement of the water is gonna have an impact on the fish if they are hibernating 5' down?

 

[RNeumann]

It’s the water circulation that causes the issue. The natural thermal layers will get disturbed. Naturally the lower you go the more constant the temps- which is what the fish like in winter. I’d do everything I could to keep that layer of water still. The just bubble enough to oxygenate in an area that won’t freeze but isn’t the deepest spot. That’s all they need. Also remember the plants and algae aren’t “taking” nearly as much oxygen from the fish in the winter either.

 

[RNeumann]

If you want the waterfall for your own enjoyment I’d add some type of dam that would prevent the water from moving near the deep spot. Or sink a 55 gal drum or something like that in the deep area that has a hole below the frozen water or the top is 6-8” below the frozen water. The water in the barrel will be fairly still for them under that scenario.
This, to me, has some risks. You could end up with water that is too cold from flowing down the waterfall.

 

[LD1]

Hence my questioning.

The waterfall is on one end of the pond lengthwise if you look at the pictures. And the pump right next to it sucking water from 2' deep.

You thing that is really messing with the thermal layers below the shelf the pump is sitting on? Down at 5.5' deep? And 50-60' across the pond?

 

[jimmyj]

Wow this is interesting. I have a similar sized pond to your first one and I just leave the circulation pump running all winter. Been doing it for years and we've never lost any fish. I wonder if because it's in a sheltered area that perhaps the water isn't getting that cold. Although the ice does freeze a good 4 inches thick around the hole, and on very cold nights it actually freezes over the whole in a "dome" due to the water agitation and I have to break it open again.

 

[LD1]

Is your pump pulling water from the very bottom?

 

[NoTrespassing]

We're in Illinois and have a very small garden pond with goldfish in it. They've survived 2 winters in that little 18 in. deep pond here in Central Illinois.

This next fact is hard for me to believe. A few years ago I put some very small bluegill in our rain barrels to eat mosquito larva. I basically forgot about them and the next spring when I was dipping out water for the dogs, a bluegill jumped out of the rain barrel and landed on the ground! I couldn't believe it survived all winter in that 70 gallon blue barrel when air temps got down below zero F.

Kevin

 

[charlton289]

I grew up in upstate CT. We had a pond that was spring feed we had bass, bull head and other kinds and we had the pond which is about 4' at the deepest. And have it freeze down about 3 ft. And in the spring when the ice melted we would see them swimming around. Don't know how they servived but they maybe it was the spring fed which the water stayed at a constant tempature