The worst experience ever with my pond was right after the first winter. We stocked it the first summer with yellow perch, LMB, and hybrid bluegills. By fall we had bass that here 10-12". We left the aerator in the deepest spot on the advice of the pro that sold us the fish and the equipment. All winter we couldn't wait to see the fish in the spring. When the ice receded there were dead fish everywhere. The bass died first and were badly decomposed. The bluegills were completely gone. The yellow perch survived for the most part but were badly stressed. Some of them you could grab out with your hand but they were still alive.
That summer we were blessed with a swarm of baby bullheads and no predators to control them. (they don't show up till mid summer when it is too hot to stock bass). We had algae like you wouldn't beleive from all the nutrients. The water smelled terrible.
We restocked the bass the following spring and caught 362 bulheads by hook and line and trapping. I am starting to regain the balance after 2 years.
Ever since then I have place my airstone in about 3 feet of water. I tie it to a post on my dock. I did not lose any fish last year and hope not to lose any this year. Plus the open water lets me keep my dock in all winter. The song birds like having the open water by the dock also.
To end a long story, do not deep water aerate through the winter in cold climates. I move mine in the fall when the water gets down into the low 50's (around Haloween) and will put it in the deep area once the surface gets over 50 and still I am careful to check the temps every day.
Be careful.
Brian
