Oxygen Needed for Fish Farming

Fish farming is the primary form of raising fish in a tank or a type of enclosure for commercial purposes. The quality of fish produced in these farms is maintained by providing sufficient oxygen, fresh water and proper food.

Oxygen

Aquatic organisms

Oxygen is essential as it is a requirement for all aquatic organisms that breathe. As such, there is a direct relationship between oxygen concentration and the quality of life of the organism.

Level of Oxygen

Fish need a specific level of oxygen for growth. Therefore, the maintenance of dissolved oxygen levels in water is of the utmost importance for the industry of fish farming. For this purpose, the air in the water of the fish farms is frequently circulated and dissolved.

Requirement of Oxygen

Bacteria

Fish excrete ammonia, a poisonous waste product. Since fish cannot tolerate this poison, aerobic (oxygen requiring) bacteria are required for detoxification. Therefore, oxygen is essential for this process of nitrification.

Lack of Oxygen

Without oxygen, anaerobic bacteria (bacteria that live without oxygen) in the water produce acids. These acids increase the acidity of the water. Additionally, these bacteria create toxic gases (ammonia, carbon dioxide and methane) in the water. The increased acidity and toxic gases are all harmful for the fish. Also, anaerobic bacteria kill the insects which the fish feed upon, eliminating the natural food source for fish.

Source of Oxygen

The primary sources of dissolved oxygen for fish farming are the atmosphere and photosynthesis of plants.

References

• Department of Fisheries and Wildlife Sciences: Fish Farming In Recirculating Aquaculture Systems
• Food and Agriculture Organization of the United Nations: Chapter 21 Aeration and Oxygenation in Aquaculture
• Environmental Defense Fund: The Promise and Perils of Fish Farming