Amphiprioninae -
Clownfish or Anemone Fish
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CLOWNFISH / ANEMONE FIELD GUIDE
Anemone fish (commonly known as Clownfish) are a
sub family of Damselfish - Pomacentridae (image 2).
They share a symbiotic relationship with host Sea
Anemones (image 1) where both creatures benefit from each
other's presence. One Anemone can host many fish.
Resembling plants, Sea Anemones are infact meat eating
animals with stinging tentacles. For more information on
Sea and Tube Anemones please visit our
Anemone page.
Anemone fish build immunity to these nematocysts by
developing a mucus coating on the body. They swim in a
unique way differentiating themselves from the prey of
the Anemone, this swimming style signals the host not to
fire its poisonous sting.
In return for shelter, they are good housekeepers,
ridding their host of unwanted parasites and leftover
food bits, they are ferocious in defending their
territory offering protection from Anemone eating fish
such as butterfly fishes.
Should an Anemone fish relocate it might take days
for their coating to develop the correct balance
sufficient to avoid being stung. Clownfish and some
Damsels are the only fish able to avoid the potent sting
of the sea Anemone.
Not all Anemones are suitable hosts some will sting and
consume potential housemates. Many species of
Anemone fish can be observed inhabiting only certain
species of anemone, for example as illustrated in Image 3
and 4, the Western Clown Anemone is generally seen
living with the H. Magnifica.
Others species of Anemone will host many different
species of Clownfish.
Clownfish have a fascinating system of hierarchy within
their community, which prevents conflict within the
group. The largest fish is always the female, the second
largest is the breeding male, the rest are all males,
juveniles usually look different to adults and they are
all hermaphrodites. When the female of the group dies the
dominant male will change to a female and take her place,
this change is irreversible. All other fish in the group
will move up one place, the next male in line then
becoming the dominant male and interestingly each fish is
exactly 20% smaller than the one above it.
When environmental conditions are suitable the
female will lay her eggs on a flat surface close to or
beneath the host Anemone, if none is available she will
move something close by.
The male externally fertilizes the eggs. The
anemone releases a compound, which the adult fish gently
blow onto the eggs and its thought that this aids in
building up the juveniles immune system. It is generally
the male who guards and tend the eggs, fanning them to
keep them oxygenated, this fascinating behavior is shown
in Image 7 & 8, we can even see the residue of the
Anemones compound on the fish's mouth in image 7.
The moons cycle dictates when the eggs hatch. The
pelagic larvae float in the water column until the time
of metamorphosis when they become juveniles.
Its very difficult for these youngsters to find a
host and unless they find an anemone without an existing
community or find a group with a vacancy due to a death
they could well be left homeless and vulnerable to
predation. Many do end up as fish food.
Fortunately the juvenile illustrated in image 10 has
found an available anemone although he must swim
carefully until his mucus covering has developed
sufficiently enough to avoid its stinging nematocysts.
