What Kills Pond Fish

Fish kill refers to all of your fish or a large portion of your fish suddenly dying. Several factors can cause pond fish to die.

  1. Vegetation

    • Too much vegtation can be disastrous.

      Vegetation that covers more than half of your pond can result in fish kill, as indicated by the Virginia Department of Game and Inland Fisheries. Too many plants in your pond will result in oxygen depletion in your pond.

    Diseases and Parasites

    • Fish that aren't cramped aren't exposed to disease.

      Fish are susceptible to viruses, bacteria, parasites and fungi. Fish that are crowded in fish ponds can have a higher mortality rate due to parasites and disease.

    Season Change

    • Lingering snow on top of an iced-over pond can kill your fish due to lack of oxygen. The snow can prevent sunlight from reaching underwater plants and allowing them to produce oxygen. Removing snow or cutting a hole in the ice can prevent fish mortality.

    Debris

    • Decomposed matter can cause fish kill.

      Vegetation that decomposes at the bottom of your pond can kill your fish. Dead vegetation, including tree leaves, require oxygen when undergoing decay, which can result in lack of oxygen for pond fish.