Fish farming or
pisciculture is the principal form of
aquaculture, while other methods may fall under
mariculture. Fish farming involves raising fish commercially in tanks or enclosures, usually for food. A facility that releases
juvenile fish into the wild for
recreational fishing or to supplement a species' natural numbers is generally referred to as a
fish hatchery. Worldwide, the most important fish species used in fish farming are
carp,
tilapia,
salmon, and
catfish.