Cold Weather Can Cause Farm Pond Fish Kills
County Extension Director
Issue/Alert Affecting Crop: Cold winter temperatures can cause fish die-offs in Florida’s farm ponds and can be cause for concern to the pond owner. Some have been reported in Calhoun County with air temperatures dipping in the upper teens at night.
Pond-turnover is a common cause fish kill cause during cold weather. Photo Credits: Les Harrison
Temperature-related fish kills are most common in the winter when extended cold can cause water temperatures to drop. The cold water can kill fish outright or may weaken them so that they become more susceptible to disease.
Cold weather can also cause a natural process called lake or pond-turnover. Turnover happens when cooled surface water sinks and mixes with deeper, oxygen-poor water (like pouring cold milk into your hot coffee). This mixing, or turnover, with oxygen poor water can cause low oxygen-related fish kills.
Fish diseases, parasites, and stresses from poor water quality, overcrowding, and human impacts can also lead to fish kills, but the reduction of dissolved oxygen in a water body is the most common cause of fish kills in Florida throughout the year.
In some cases cold temperature-related fish kills help limit the spread of invasive, non-native fish species because non-native species such as tilapia are especially susceptible to cold weather.
Aerating your pond is one way in which to reduce the chances or severity of a fish kill caused by pond-turnover.