The Clownfish, or Anemonefish, are a subfamily of the family Pomacentridae. There are currently 27 species, of which one is in the genus Premnas and the rest are in the genus Amphiprion. The other pomacentrids are called damselfish.

Clownfish are native to wide ranges of the warm waters of the Pacific; some species ranges overlap others. Clownfish are not found in the Atlantic. Clownfish live in a mutual relationship with sea anemones. Once an anemone has been adopted, the clownfish will defend it vigorously. However, clownfish in an aquarium environment can exist very well without an anemone. (This may be advisable as anemones are extremely difficult to keep alive even for experienced aquarists.) To avoid the stings of their host anemones clown fish have secretory cells producing a layer of mucus on their bodies. The mucus is based on sugar rather than proteins so anemones fail to recognize the fish as food and do not fire their nematocysts, or sting cells.

Clownfish are among the few marine fish that can be bred in captivity in commercially-viable quantities at the time of this writing. Hobbyists are advised to purchase captive-born clownfish (and other marine animals) whenever possible. The Amphiprions are attractive in colour and usually wear bright colours. Example: orange, black, and white. They are good for a marine aquarium because they are friendly and easy to feed. They adapt well in captivity and can be easily studied for scientific research. These warm water fish have a higher metabolism which makes them more active than the cold-water fish.

Clownfish lay eggs on any flat surface close to or under protection of their host anemones. These eggs are cared for by the male and hatched under complete darkness after a period of 7 to 10 days. Hatching occurs in a natural rhythm directly connected to the phases of the moon. Clownfish are omnivorous, their diets range from flakes to meat. They feed mostly on copepods and mysids, the undigested excrement from their host anemones.

Clownfish are relatively small organisms, fish in aquaria can grow to 9 cm (3.5 inches) in length, fish in the wild can grow to a length of 12 cm (5 inches).

Reproduction

A school of clownfish is always built into a hierarchy. At the top is always a female fish, the rest are male, ranking from the most dominant to the least dominant. If the female clownfish should die or be removed from the school, the most dominant male then changes into a female, and the rest of the males move up a rank on the hierarchy. This process of sex changing is called spawning. This process is common in the marine environment and is a means of keeping the species in existence.

References in media

Clownfish featured prominently in the 2003 Pixar_animated movie Finding Nemo. Despite the content of the movie _ wherein a young clownfish's father must rescue his son after being stolen to be sold as a pet _ public demand for clownfish as pets has tripled shortly after its release. Some environmental protection activists regard this as a catastrophe as the species is already facing the threat of extinction due to a reduction of its natural habitat (coral reefs) which in turn is due to global climate changes as well as pollution of the seas.

It is also feared that people may have attempted to send fish back into the open sea by flushing them down the toilet as demonstrated in the film; unfortunately, they will not be able to survive the canalisation or the sewage plant. Another problem is that many buyers lack basic knowledge - like needing a saltwater tank - to take care of such speciality fish.