CLOWNFISH
Clownfish are native to wide ranges of the warm waters
of the Pacific and Indian Oceans; some species ranges
overlap others. Clownfish are not found in the Atlantic
Ocean. Clownfish live in a mutual relationship with sea
anemones, or in some cases settle in some varieties of
soft corals, or large polyp stony corals. Once an
anemone or coral has been adopted, the clownfish will
defend it.
The anemone is required in nature because reef life is
dangerous for small, brightly coloured fish; in an
aquarium lacking predators it is not needed. For this
reason, clownfish never stray far from their host. In an
aquarium, where they don't have to forage for food, it is
very common for clownfish to remain within 6 to 12
inches of their host for an entire lifetime.
Clownfish and damselfish are the only species of fish
which can avoid the potent stings of an anemone.
There are several theories for how this avoidance is
accomplished. Firstly, the slime coating of the fish may
be based on sugar rather than proteins so anemones
fail to recognize the fish as food and do not fire their
nematocysts, or sting organelles.
Secondly, the mucous coating may mimic the
anemone's own coating, a theory that is bolstered by
the fact that it takes several days for a clownfish to
adapt to a new species of anemone. There is no
adaptation period when a clownfish is moved to
another anemone of the same species.
Thirdly, their unique movements, which are unlike any
other fish, may let the anemone know that they are not
food. This theory is bolstered by the fact that juvenile
clownfish, which have no coating, will immediately
seek refuge in any compatible anemone and will not be
stung. Juvenile clownfish will not survive for long
without the protection of an anemone, and few find one
before being eaten.
Clownfish live in their anemone in groups. Usually a
female lives with other males. When the dominant
female dies the head male changes sex and becomes
the female.
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.
From Wikipedia, the free encyclopedia
