Where Do Clownfish Live? Reefs and Anemone Homes

The clownfish range across the Indo-Pacific

The 28 or so species of clownfish, also called anemonefish, are spread across the Indo-Pacific, the vast tropical region that joins the Indian Ocean to the western and central Pacific. They are found from the Red Sea and the coast of East Africa in the west to French Polynesia in the east, and from southern Japan in the north to Australia in the south.

Clownfish are most diverse near the middle of this range. In parts of Southeast Asia and northern Australia, as many as 12 species can live in the same area. Toward the edges, the number drops sharply: the Red Sea and French Polynesia each have just one species. Genetic studies suggest clownfish first evolved in the waters of the Malay Archipelago, the island region between Southeast Asia and Australia, and spread outward from there.

Some species are widespread. Clark’s anemonefish has the largest range of any clownfish and lives across much of the Indian Ocean and western Pacific. Others have small ranges and live only around a few islands or reefs.

Where does the ocellaris clownfish live?

The ocellaris clownfish, the orange-and-white species most people picture as “Nemo”, lives in the eastern Indian Ocean and western Pacific. Its range runs from the Andaman and Nicobar Islands, Thailand and Malaysia through Singapore, Indonesia and the Philippines, south to northwestern Australia and north to Taiwan and the Ryukyu Islands of southern Japan. A natural black form lives off the Northern Territory of Australia.

Its look-alike, the orange clownfish, lives farther east, in northern Queensland, including the Great Barrier Reef, and around New Guinea and the Solomon Islands.

Why clownfish need an anemone

A clownfish’s real address is not just a reef but a particular anemone. Clownfish depend on their host for shelter from predators, a safe place to lay eggs and somewhere to rest at night, so they can only live where suitable host anemones grow. Ten anemone species serve as hosts, and each clownfish species uses its own set of them. How they survive among stinging tentacles is explained in Why don’t clownfish get stung by anemones?

Host anemones carry tiny algae in their tissues that make food from sunlight, so they grow on hard surfaces in clear, sunlit water, often where currents bring extra food. The magnificent sea anemone, one of the most important hosts, lives across the Indo-Pacific from East Africa and the Red Sea to Polynesia, usually from the surface to about 20 m (65 ft) deep. The ocellaris clownfish lives with just three hosts: the magnificent sea anemone, the giant carpet anemone and Mertens’ carpet anemone.

How deep do clownfish live?

Because their hosts need light, most clownfish live within about 20 m (65 ft) of the surface, on reef flats, reef slopes and in lagoons, although Clark’s anemonefish has been found as deep as about 60 m (200 ft). The ocellaris clownfish is usually found between about 1 and 15 m (3–50 ft) deep, often in calm, sheltered lagoons and on outer reef slopes.

Different clownfish species on the same reef can avoid competing for the same hosts by living in different zones, for example near shore, in the middle of a lagoon or on the outer reef.

How far do clownfish stray from their anemone?

Not far. An adult clownfish usually stays within a few meters of its anemone for its whole adult life. Where predators are scarce, a clownfish may forage over an area of up to about 20 square meters (220 square feet), but where there are many predators it stays in the water just above the tentacles. The large breeding pair ventures farthest, while the smallest fish rarely leave the anemone at all.

The only long journey happens right after hatching. Clownfish larvae drift in the open sea for about one to two weeks before settling on a reef. Studies of orange clownfish in Papua New Guinea found that many young return to settle on the reef where they hatched, while others travel tens of kilometers. Young Oman anemonefish have been recorded traveling more than 400 km (250 mi) on ocean currents.

Threats to clownfish homes

The biggest threat to clownfish is the loss or bleaching of their anemones. Like corals, host anemones can expel their algae and turn white during marine heatwaves. Bleached anemones may shrink or die, and clownfish living in them produce fewer eggs. During the 1997–98 El Niño, bleaching wiped out the host anemones in one area off Sesoko Island, Japan, along with the local population of pink skunk clownfish. The same heat stress drives coral bleaching.

Other threats include ocean acidification, which can dull the senses that clownfish larvae use to find a reef and a host, collection of clownfish and anemones for the aquarium trade, and coastal development that clouds shallow water with sediment. Clownfish tend to be more common inside marine protected areas, where collecting is forbidden.