Pond Boss Forums INTRO Questions & Observations Finding dead fish under ice

It is not normal but not unusual for several larger fish to die at early ice cover. We can assume deaths were not due to low DO and not a typical winter kill. My first guess at cause of deaths was due to fall or late summer angling and mishandling of the fish. Mishandling of fish stresses them most often by removing the protective slime coat which commonly leads to cold water fungus. Onset of cold water makes it harder for the fish to recover from angling stressors and other stressors. Cooling of water and crowding of fish results in lowering the amount of available fish foods; both can act as stressors. The cold water season is usually the hardest of all seasons for the fishes.

We have to remember a few other things. Age of the HBG that may have normal life span of 4-7yrs. . Fish do not live forever. Older fish do not have the health vitality of younger fish. Sometimes the life span of some fish is relatively short and can be shortened due to added stressor/s. An example would be pnemonia in granparents. Rapid onset of cold water and strong winds can quickly strongly mix the pond and create lower than 39F water which acts as an added stressor. As long as you only lost a few fish and not high numbers such as 50-80, I would not be overly concerned. I assume there are numerous other large HBG that survive and you lost only a few of the weakest individuals.