Aquaculture is defined by the Food and Agriculture Organization of the United Nations as the farming of aquatic organisms including fish, molluscs, crustaceans and aquatic plants with some sort of intervention in the rearing process to enhance production, such as regular stocking, feeding and protection from predators.

There are various stages of aquaculture operations including:
  • a hatchery operation which produces fertilised eggs, larvae or fingerlings
  • a nursery operation which nurses small larvae to fingerlings or juveniles
  • a grow-out operation which farms fingerlings or juveniles to marketable sizes.

Depending on the species being farmed, aquaculture can be carried out in freshwater, brackish water or marine water.

The systems used for aquaculture include but are not limited to ponds, fibreglass or concrete tanks, pens, and floating cages.

Farming can be extensive, semi-intensive or intensive, depending on the level of input and output per farming area and the stocking density. Intensive aquaculture involves intervention in the growing process, such as with supplemental feeding and water aeration, whereas extensive aquaculture allows the stock to grow on its own, using natural food sources and conditions.

Aquaculture can be used to produce fish, molluscs, crustaceans and aquatic plants for human consumption or for producing ornamental species and other products.

Aquaculture can also be operated with other agriculture activities forming an integrated aquaculture/agriculture system.