Florida Warm Water Fish Kills – Water Temperatures are rising with the temp!

cold water map

Warmer weather brings warmer water, less dissolved oxygen, and fish kills.

Fish - Large Mouth BassWelcome to summer. It seems to have started much too soon this year.  Before we realized it, the temperatures hovered near 90 with a heat index close to 100.  When the temperature rises, dissolved oxygen levels in lakes and ponds drop and fish kills occur.


Effects of Low Dissolved Oxygen

Summer fish kills can occur when there are low concentrations of dissolved oxygen in your lake or stormwater pond. Some of the effects are:

  • Nutrient build up
  • Increase in algae growth
  • Increase in bottom muck due to the slow down of oxidation of organic waste
  • Rotten egg odors from toxic gasses (hydrogen sulfide) increase
  • Fish gasping for breath at the water surface resulting in stress and possible mass fish kills
  • Temperature differences between top and bottom levels further reduce oxygen at lower levels causing water stratification

Fish - Snook

Fish Need Oxygen Too

Warm water doesn’t contain additional oxygen that fish need to breathe, therefore, they can become inactive and sluggish. They can also struggle to breathe when algal growth expands, muck buildup occurs and Mother Nature lets loose another Niagara Falls type rain event. The fish in the lake may be coming to the top and gasping for air before going back under. Fish need oxygen to breathe like we do. Don’t let them suffer.

Aeration Can Prevent a Summer Fish Kill

To avoid the unpleasant surprise of dead fish floating, add bottom diffused aeration to eliminate stratification. A submerged aerator keeps the water moving thus avoiding stagnation and improves the dissolved oxygen level in lakes and storm water ponds. The fish will be able to breathe easier and therefore, live. There are several different models available depending on the size and depth of your lake or pond. Aeration is a sustainable and affordable way to avoid a fish kill. Keep your fish healthy and thriving during the hot summer months.


If you see fish under stress or dying in your lake, please call us at 800-432-4302 for help