Fish Kills

If you notice large numbers of fish staying near the surface of your pond early or late in the day, see fish at the surface gulping air, or your fish suddenly stop eating when you feed them, you may be in danger of a fish kill. Most fish kills occur between June and October, although they can occur at any time of year. The most common cause of fish kills in lakes and ponds in our region is oxygen depletion, which occurs when oxygen consumption by aquatic animals, plants, and decaying organic material exceeds the water’s available oxygen supply. There are a number of dynamics that can contribute to a critical oxygen depletion situation, including weather conditions, pollution, and overstocking/overfeeding of fish. Once dead and dying fish are seen, it’s usually too late to stop the kill, and kills related to significant water contamination or fish disease are generally not preventable. However, proper lake management does help to prevent fish kills related to oxygen depletion; controlling algae and aquatic nuisance vegetation, installing and maintaining beneficial aquatic plants, and following appropriate guidelines for fish stocking, feeding, and fertilization all contribute to keeping a lake or pond in good balance. It’s also important to have chemical treatments applied by licensed applicators. If you have concerns about the health of the fish in your pond, or any other inquiries about fish stocking and management, contact Aquascape Environmental at 678-445-0077, or the Georgia Department of Natural Resources at 800-241-4113.