One of the problems with letting it run all winter is that especially during
a cold night, ice dams can form which can divert water outside the pond,
possibly causing a catastrophic loss of water and subsequent loss of the
fish. For this reason it is always advisable that your pump not be located
at the lowest level on the pond, so that in the event of something like this
happening, all the water is not pumped out.

It's also advisable to run an airstone or other aerator during the winter,
perhaps coupled with a stock tank heater, to keep enough oxygen in the water
and avoid a complete freeze-up on the surface.

Happy Ponding,
Tim

"Keith Nuttle" wrote in message
...
I live in central indiana. My pond is about 1400 gal 120 sqft with
three levels and sluice to from each level to the next and the bottom
level is pump to the top level.

Should or can I let this pond run all winter?

If not when should it be turned off?