Have you ever known a fellow fish enthusiast who got up one morning only to discover that all of his fish were dead? A possible cause of this shocking experience is oxygen depletion. If not treated, fish will literally suffocate to death. Fish cannot survive in an oxygen depletion environment and it is a common cause of mass mortality in the aquarium.

The good news is that oxygen depletion can be avoided by testing the water regularly and aerating the aquarium properly.


Fish hang just below the surface of the water and gasp for air.


You may be able to identify oxygen depletion by observing your gasping fish, but they best way to diagnose this problem is by buying a water test kit and testing the water. A proper oxygen concentration will vary according to the type of fish, the size of the aquarium, how many fish are in the aquarium and the presence or absence of live, aquatic plants. Remember that gasping fish could signal a gill disease as well.

  1. Check the filter system and aeration to ensure in proper working order.
  2. Avoid overcrowding the tank.
  3. Consult your aquatics specialist for guidance.

GOOD - if diagnosed and treated immediately. Although oxygen depletion can cause mass mortalities, treating the problem immediately can have your fish swimming and breathing happily again in no time.


Get the proper aeration system for your size aquarium. Keep the aquarium clean, especially the bottom of the tank where uneaten food can accumulate and decompose, utilizing valuable oxygen in the decomposition process.