Fish farming is the principal form of aquaculture

Aquaculture

Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...

, while other methods may fall under mariculture

Mariculture

Mariculture is a specialized branch of aquaculture involving the cultivation of marine organisms for food and other products in the open ocean, an enclosed section of the ocean, or in tanks, ponds or raceways which are filled with seawater. An example of the latter is the farming of marine fish,...

. Fish farming involves raising fish commercially in tanks or enclosures, usually for food. A facility that releases young (juvenile) fish into the wild for recreational fishing

Recreational fishing

Recreational fishing, also called sport fishing, is fishing for pleasure or competition. It can be contrasted with commercial fishing, which is fishing for profit, or subsistence fishing, which is fishing for survival....

 or to supplement a species' natural numbers is generally referred to as a fish hatchery

Hatchery

A hatchery is a facility where eggs are hatched under artificial conditions, especially those of fish or poultry. It may be used for ex-situ conservation purposes, i.e. to breed rare or endangered species under controlled conditions; alternatively, it may be for economic reasons A hatchery is a...

. The most common fish species raised by fish farms are salmon

Salmon

Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

, carp

Carp

Carp are various species of oily freshwater fish of the family Cyprinidae, a very large group of fish native to Europe and Asia. The cypriniformes are traditionally grouped with the Characiformes, Siluriformes and Gymnotiformes to create the superorder Ostariophysi, since these groups have certain...

, tilapia

Tilapia

Tilapia , is the common name for nearly a hundred species of cichlid fish from the tilapiine cichlid tribe. Tilapia inhabit a variety of fresh water habitats, including shallow streams, ponds, rivers and lakes. Historically, they have been of major importance in artisan fishing in Africa and the...

, European seabass

European seabass

The European seabass, Dicentrarchus labrax, also known as Morone labrax, is a primarily ocean-going fish that sometimes enters brackish and fresh waters. It is also known as the sea dace...

, catfish

Catfish

Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

 and cod

Cod

Cod is the common name for genus Gadus, belonging to the family Gadidae, and is also used in the common name for various other fishes. Cod is a popular food with a mild flavor, low fat content and a dense, flaky white flesh. Cod livers are processed to make cod liver oil, an important source of...

.

There is an increasing demand for fish and fish protein, which has resulted in widespread overfishing

Overfishing

Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....

 in wild fisheries.