Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Fish Kill in West Central Indiana

The trees shouldn't have done anything other than maybe scare a few fish.

It all depends on the BOD (Biochemical Oxygen Demand) of the things in the pond. Large fish need more O2 than smaller ones. If there were a lot of underwater weeds in your pond, when they decompose during the winter, they need O2. Ponds with mucky bottoms need more O2 than clean bottom ponds, etc., etc.