Clownfish (Anemone Fish, Amphiprion): ID and Facts

Clownfish, anemonefish and anemone fish all name the same group: about thirty species in the genus Amphiprion that live inside the tentacles of sea anemones. The fish everyone pictures is Amphiprion ocellaris, also sold as the false percula or common clownfish.

Identification starts with the bands. A. ocellaris is orange with three white bands, at the head, middle and tail, each thinly outlined in black. The middle band bulges forward in the centre, which is the feature people learn first. Counting dorsal spines separates it from its close relative: A. ocellaris has 10 to 11, while A. percula has 10 or rarely 9, and A. percula carries much thicker black outlines around the white.

Other Amphiprion species look quite different — maroon, dusky brown, or with a single head band — so band count and colour are the first thing to check, not the last. Photograph it and the app identifies it if you want the species name from a tank or reef photo.

A clownfish is protected by a layer of mucus on its skin that keeps the anemone's stinging cells from firing. The relationship is not automatic: a fish moving into a new anemone acclimates first, rubbing its belly and ventral fins against the tips of the tentacles in short contacts until it can settle in.

The partnership works both ways. The anemone gives the fish a place where almost nothing can follow it, which is why clownfish barely leave home. In return the fish drives off anemone-eating fish, and its movement among the tentacles helps water circulate.

A. ocellaris is specific about its host, using Heteractis magnifica most often and Stichodactyla gigantea or Stichodactyla mertensii as alternatives. That is also why a wild clownfish is so tied to one spot on a reef: without a suitable anemone it has nowhere safe to be.

Clownfish are protandrous hermaphrodites. A group in one anemone has a strict order: the largest fish is the female, the second largest is the breeding male, and the rest are smaller non-breeding males held down by aggression from the female.

When the female dies, the breeding male changes sex and becomes the new female, and the largest of the waiting juveniles moves up to breeding male. The sequence only runs one way — a female cannot revert.

This is the part that the popular film gets backwards, and it matters for aquarists too. Adding two similar-sized clownfish to a tank usually ends with one dominating and the pair sorting itself into a female and a male. Adding a third of similar size often ends badly.

Clownfish eat algae, copepods, isopods and zooplankton, along with dead anemone tentacles and scraps of prey the anemone did not finish. They are easy feeders, which is one reason they do well in captivity.

Breeding happens on the rock or substrate next to the host anemone. A female lays roughly 100 to 1,000 orange eggs over one to two hours, and they hatch in about six to eight days, after which the larvae drift as plankton for around eight to twelve days before settling on a reef and finding an anemone of their own.

Eggs are taken by damselfishes, wrasses and brittle stars, but adults inside an anemone face little predation. Florida Museum records no documented danger to humans from this species.

Clownfish are one of the success stories of marine aquaculture. They breed readily in captivity, and captive-bred stock is widely available, which takes pressure off wild reef populations. Buying captive-bred is the single most useful thing a hobbyist can do here.

Captive-bred clownfish also tend to be easier animals: they accept prepared food from the start, they tolerate aquarium conditions better than wild-caught fish, and they do not need a host anemone to be healthy. Many settle in and use a coral, a powerhead or a corner of the tank as a substitute home.

If you do want an anemone, note that the anemone is the harder animal to keep — it needs strong light and stable water chemistry — and that pairing the wrong anemone species with the wrong clownfish often simply does not take.

Amphiprion is the genus that holds every clownfish. The name, coined in 1801, comes from the Greek amphi (on both sides) and prion (saw), after the serrated edges on the gill covers (Wikipedia). The genus sits inside the damselfish family, Pomacentridae.

The count moved recently. Before 2025, 28 living species and two hybrids were recognised; in 2025 the Polynesian anemonefish, A. maohiensis, previously treated as a colour form of the orange-fin anemonefish, was named as a new species, making 29 (Wikipedia). The maroon clownfish, long kept in its own genus Premnas, was placed inside Amphiprion after two large genetic studies in 2021. Pages that still say 28 species, as a diving site we checked does, or that list Premnas separately, are describing the older arrangement.

Clownfish live in the Red Sea, the Indian Ocean and the Pacific, and none are native to the Caribbean (Els Van den Borre). A common name that is often searched on its own: Amphiprion ocellaris is the common clownfish or false clown anemonefish (Animal Diversity Web), also sold as the false percula.

A sea anemone is not a fish, and not a plant either. It is a predatory invertebrate animal in the order Actiniaria, in the same phylum, Cnidaria, as corals and jellyfish, and like them it catches food with stinging cells. Most are 1 to 5 cm across, though they can inflate well beyond that (Wikipedia).

Only a small set of anemones host clownfish: 10 species worldwide (Wikipedia), and many individual anemones of those species have no clownfish at all. Some clownfish are specialists and others are not; Clark's anemonefish uses at least ten different anemones (Els Van den Borre).

Clownfish are not the only tenants. Wikipedia's sea anemone article lists cardinalfish such as the Banggai cardinalfish, juvenile threespot dascyllus, the anemone goby, juvenile painted greenling, crabs including porcelain crabs of the genus Neopetrolisthes, shrimps of genera such as Periclimenes and Thor, mysid shrimps and various snails. In an aquarium, that list is not a shopping list: an anemone stings fish that are not adapted to it, and Wikipedia's seahorse article names sea anemones among the animals to keep away from seahorses.

An established clownfish is not stung, but it has to earn that. Wikipedia describes clownfish acclimating to a new host by touching, nipping and fanning the tentacles over a period of minutes to days. Protection is attributed to the mucus coat, and researchers still debate the mechanism, whether the mucus is thick enough to block stinging cells, or whether it mimics the anemone's own molecules or bacteria; Wikipedia calls the evidence ambiguous.

The partnership gives the anemone something too. In experiments, a clownfish offered small and large pieces of food ate the small ones and carried the large ones to its anemone (Wikipedia). Anemones depend on clownfish less than clownfish depend on anemones, which is why an anemone can thrive empty while a clownfish without one is exposed on the reef.

Most clownfish are not rare. As of 2025, 25 of the 29 species had been assessed by the IUCN, and most are Least Concern; the exceptions are McCulloch's anemonefish, listed as Vulnerable, and the wide-band anemonefish, listed as Data Deficient (Wikipedia). Some species do have small ranges, such as the Red Sea clownfish, found only in the Red Sea.

The species everyone knows, Amphiprion ocellaris, has not been evaluated by the IUCN and has no CITES listing (Animal Diversity Web). Local depletion is documented, though. Animal Diversity Web notes that aquarium demand has reduced populations in some locations, a 2014 study linked collection to declines of ocellaris clownfish and their anemones around the Spermonde Archipelago in Indonesia, and a 2019 study found slow recovery over ten years during a collecting pause in Australia's Keppel Islands (Wikipedia). Ocean warming and acidification are the other named threats. Buying captive-bred fish, which the aquaculture industry supplies in quantity, avoids adding to that pressure.

Clownfish are not a food fish. None of the sources we checked (Wikipedia, Animal Diversity Web and the Florida Museum) record them being caught or sold for food; Animal Diversity Web lists their economic value to people as the aquarium trade, research and education, and a large A. ocellaris reaches only about 11 cm. The Florida Museum states plainly that the species is not harvested for human consumption. That is not a statement that eating one is safe: we have no data either way, and a pet or reef fish is not food.

If you compare sources you will find clownfish numbers that do not match. The differences are real, and they come from different species and different settings:

• Eggs per spawning: 100 to 1,000 for A. ocellaris (Florida Museum), up to 1,000 across the genus (Wikipedia), and 150 to 200 per cycle, repeating every three weeks, in a diving guide's summary (Els Van den Borre).
• Hatching time: 6 to 7 days (Wikipedia) against 8 to 14 days (Els Van den Borre). Water temperature changes development speed, so both can be right in their own conditions.
• Lifespan: an estimated 6 to 10 years in the wild for A. ocellaris (Animal Diversity Web), 3 to 6 years in a general diving summary, while Wikipedia notes clownfish can live over 20 years and the orange clownfish is estimated to reach 30.

For identification the lesson is simple: quote a number together with the species it belongs to. A photo run through the app gives you the species first, and the right numbers follow from that.

The best anemone for a clownfish is one of the species it hosts with in the wild, and that depends on the clownfish. Only 10 sea anemones host clownfish: the malu, sebae, magnificent, corkscrew tentacle, Mertens' carpet, Haddon's, giant carpet, adhesive, bubble-tip and beaded sea anemones (Wikipedia). Some clownfish use many of them, such as Clark's anemonefish, which uses all ten; others, including the tomato, maroon and McCulloch's anemonefish, use a single species (Wikipedia).

• For ocellaris clownfish: the magnificent sea anemone is the main host, with the giant carpet and Mertens' carpet anemones as alternatives, as the host field at the top of this page shows. Wikipedia now files the magnificent anemone as Radianthus magnifica, formerly Heteractis magnifica. It hosts 13 clownfish species and its disc is usually 20 to 50 cm across, sometimes 1 m, so it needs a large tank, strong light and current (Wikipedia)
• Bubble-tip anemone (Entacmaea quadricolor): hosts 14 clownfish species, around half of all anemonefish, including Clark's, tomato, orange-fin and maroon, and grows up to 30 cm across (Wikipedia). Wikipedia advises that the tank be at least six months old and stable, with medium lighting, and that without enough light the anemone expels its symbiotic algae, bleaches and dies

Match the anemone to your clownfish species first, and to your tank second.

Shops sell more anemone types than the ten natural hosts. On 25 September 2026, Top Shelf Aquatics listed bubble-tip anemones at $149.99 to $499.99 depending on colour morph, rock flower anemones at $69.99 to $159.99, Condylactis anemones at $49.99 to $59.99 and a pink tube anemone at $119.99. Of these, only the bubble-tip is on Wikipedia's list of the 10 clownfish host species, so a clownfish may ignore the cheaper ones.

They can take small fish in general. Sea anemones catch prey with stinging cells and can swallow items as large as crabs, molluscs and small fish (Wikipedia). A clownfish is protected only after it acclimates to its host by touching and nipping the tentacles over minutes to days (Wikipedia), so the risky moments are when a clownfish meets an anemone for the first time, or when a weak or sick fish can no longer keep its place. Other fish in the tank have no protection at all. We found no measured figure for how often aquarium anemones eat clownfish.

Wikipedia notes that with no predators, clownfish can thrive in captivity without sea anemones, which is why many keepers skip the anemone entirely. Captive-bred fish often adopt a soft coral, a powerhead or a corner of the tank instead, as covered above. Adding an anemone is a decision about the anemone's needs, not the clownfish's.