Oxygen levels are usually highest at mid-afternoon and lowest just before sunrise. Fish kills usually occur when more oxygen is consumed during the night hours than is produced during daylight hours. Warm water does not contain as much oxygen as cold water. Thus,
during warm weather months, mismanagementof ponds by overstocking, overfeeding, overfertilization,pollution from barns and feedlots or chemical treatment of aquatic weeds can result in oxygen depletion and fish kills.Several calm, cloudy days during warm weather can also result in oxygen depletion and fish kills.