Clownfish

Clownfish are small reef fish with nearly 30 species. The facts on this page refer to the best-known species, the ocellaris clownfish (Amphiprion ocellaris). It is easy to recognise by its bright orange body and three white bands edged in black.

Where does it live?

It lives on shallow coral reefs and in lagoons in the eastern Indian Ocean and western Pacific. It is always found with certain species of sea anemone.

What does it eat?

It is an omnivore that eats zooplankton, small crustaceans and algae. It may also eat scraps left from the anemone's prey.

Partnership with the sea anemone

The clownfish lives among anemone tentacles that are deadly to other fish. A special mucus layer covering its skin is thought to prevent the anemone's stinging cells from firing. The anemone protects the fish from predators; the fish cleans the anemone, chases away some predators and provides nutrients through its waste.

Behaviour and social life

An anemone is usually home to a group made up of one female, one breeding male and several smaller males. All clownfish are born male. When the female, the largest in the group, dies, the breeding male becomes female and the next-largest male takes his place.

Young

Eggs are laid on a rock surface right next to the anemone. The male cleans and guards them until they hatch. The young drift in open water as plankton for a while and then find their own anemone.

Conservation status

There is no global IUCN assessment for the ocellaris clownfish. Coral reef decline from warming and bleaching affects both anemones and clownfish. Collection from the wild for the aquarium trade also puts pressure on some areas.

Fun facts

• Clownfish rarely stray far from their anemone.
• Clownfish were among the first marine fish to be bred successfully in aquariums.
• The sizes of clownfish in an anemone follow their rank in the group.