I don't have aeration yet, and probably can't get to doing it until this summer.

If my pond is in danger of freezing over this winter, are there simple ways to try to prevent fish kill? I have a Honda GX20 water pump and inlet/outlet hoses, but it has a small gas tank and operating it in sub-freezing temps doesn't sound real appealing.

Are there any other temporary measures I should consider if I only need to keep it ice free for a few days?

Bronco it's not the ice that kills the fish, its the snow on top of it blocking the sun light. If your plants get no light eventually they will die back and the dead plants will rot and use up the oxygen. This does not happen overnight. I recently measured 18" of ice on my ponds however there is no snow on them right now. I just dropped in a camera and all the fish are still smiling at me. I do aerate and you should too, but a little ice won't hurt. Think of how many natural lakes and ponds without aeration there are that freeze over for months each year.

Woodster has good advice!!

We are going to be putting in an aeration system this Monday on a frozen 3 acre dam, we have the time, and love ice. There is 22 inches of ice right now. and not the most clear.

How hard and long does your neck of the woods freeze??

do you not run your stream diversion in the winter??

a little running water flowing into a frozen lake from open water/air should be oxygenated?

Very reassuring. Thank you for the replies. Over many decades there was only one year where the pond froze enough to walk on it. Most years it does not completely freeze over.

Fish, the stream diversion does not run in winter. I might start diverting in future winters once I install a microhydro turbine, but except for that there is little benefit to bringing in more water in winter.

Having said that, the snowpack in our part of the Sierra Nevada mountains went to 180% of normal after the last storms. Very nice change from years of drought. We should have good creek water and much more healthy trees next year. More than 100 million pine trees have died state wide due to drought, drought related beetle problems, and fires.