During summer, hot, dry weather and low water levels can trigger fish kills in ponds, lakes, and rivers. Although summer fish kills rarely affect entire fish populations, these events can impact local ecosystems, disrupt fishing, and alarm the public.

Summer fish kills are often caused by low oxygen levels in the water. When periods of excess heat occur along with little or no rainfall, water levels and oxygen levels can drop, resulting in increased stresses on fish. These same conditions can trigger algal blooms which further deplete oxygen levels in bodies of water.