Clownfish

Instantly recognizable thanks to its bright orange coloring and distinctive white banding, the clownfish — which is also known as the false clownfish (actually the one with the famous coloring), anemonefish, and false percula — gained worldwide fame thanks to the popularity of the 2003 film Finding Nemo. This species is found in large, stable populations in shallow waters off the coasts of Australia and Southeast Asia, as well as in the Red Sea, the Indian Ocean, and the western Pacific Ocean. Clownfish are part of a genus that includes more than 30 species.

4 Incredible Clownfish Facts

• Clownfish perform an intricate dance with their host anemones before moving in, which allows them to develop an immunity to the anemone’s venom, which is released via stinging tentacles.
• All clownfish are born male. These protandrous hermaphrodites can change sex to become female later in life, depending on their social hierarchy.
• Male clownfish do most of the work when waiting for the eggs to hatch, including fanning the eggs and consuming ones that are not fertile.
• Although not endangered, these fish are at risk as coral reefs around the world become depleted. It is believed that the movie Finding Nemo caused a surge in the harvesting of these fish, which may have intensified damage to coral reef systems.

Classification and Scientific Name

The scientific name for the false clownfish is Amphiprion ocellaris. The term Amphiprioninae is derived from Greek, with “amphi” meaning “both sides” and “prion” meaning “saw.”

Amphiprion is a genus of ray-finned fish that makes up all but one of the species of clownfish or anemonefish in the subfamily Amphiprioninae of the family Pomacentridae. That one species outside the genus Amphiprion is the maroon clownfish, Premnas biaculeatus. These fish are members of the class Actinopterygii and the order Perciformes.

Types

Across more than 30 species, these fish boast an array of different appearances and colorings, such as yellow, orange, or a reddish or blackish color, and many show white bars or patches. The most well-known species, by far, is the false clownfish of Finding Nemo fame. This fish has bright orange coloring and three broad, white bands that are outlined with thin bands of black.

The false clownfish is nearly indistinguishable from A. percula, the orange clownfish that is a member of the same genus. One distinction is that the black bands outlining the white bands are thicker than on the false clownfish.

Examples of other species of clownfish include:

• Skunk clownfish, A. akallopisos
• Yellowtail clownfish, A. clarkia
• Fire clownfish, A. melanopus
• Saddleback clownfish, A. polymnus
• Whitesnout anemonefish, A. mccullochi
• Pink anemonefish, A. perideraion

The Damselfish is a similar type of fish that belongs to the same Pomacentridae family. Clownfish and Chromis Damselfish can cohabitate well in a fish tank.

Appearance

These fish grow to an average length of 4.3” and an average weight of 7.05 ounces. The most recognizable species, the false clownfish, has bright orange coloring that is set off by broad, white bands outlined in black. This fish has a rounded tail, and its dorsal fin is lined with 11 spines. They are nearly identical to A. percula, the orange clownfish or clown anemonefish, and they start out life with clear or transparent skin that gradually attains its coloring and markings.

Distribution, Population, and Habitat

These fish are found in coral reefs primarily off the coast of Australia and Southeast Asia. They inhabit the waters of the Red Sea, the western Pacific Ocean, and the Indian Ocean, but they are not found in the Atlantic Ocean, the Caribbean Sea, or the Mediterranean Sea.

Population estimates for them are not available, but they are abundant and widespread in endemic areas. These fish are not endangered, so they are not listed as such on the IUCN list. However, the coral reefs where they live are endangered, with 15% to 30% of the reefs having disappeared within this generation. After the movie Finding Nemo debuted in 2003, demand for these fish for home aquariums skyrocketed. It is believed that an increase in hunting for the elusive fish contributed to coral reef damage.

Relationship with Anemones

Anemonefish, also known as the clownfish, get their name because they form symbiotic relationships with sea anemones. This relationship developed from the evolution of the anemone as a host to the clownfish three separate times in the anemone’s history. The first time occurred over 65 million years ago. Anemones likely developed as a species first, and in a different part of the world. Then clownfishes adapted to live with them, probably in the Western Pacific Ocean originally.

Sea anemones, creatures that anchor to the ocean floor and use tentacles to draw in food, come in various species. However, the fish primarily form symbiotic relationships with three species, or types, of sea anemone: Heteractis magnifica, Stichodactyla gigantia, and Stichodactyla mertensii.

Sea anemones release toxins from their tentacles. A clownfish evades this issue by performing an intricate dance with the anemone it wants to claim. As it gently touches the anemone’s tentacles, a clownfish becomes acclimated, developing a layer of mucus that scientists believe gives it immunity to the anemone’s lethal stings. Once entrenched, the fish benefit from this relationship with increased protection and safer access to food; sea anemones benefit because clownfish drive away would-be attackers and preen, or remove parasites from, their bodies.

Predators and Prey

What Eats Clownfish?

Thanks to the protection granted to them by their host anemones, anemonefish face very few predators. The exception is when they have to dart out for food; at those times, they are hunted primarily by larger, more aggressive fish.

What Do Clownfish Eat?

These fish are omnivores, so they eat both plants and other animals. They primarily subsist by feeding on zooplankton and phytoplankton. Known as “plankton pickers,” these fish find and target specific plankton floating in their water column before eating them. This is as opposed to filter-feeding, which involves filtering huge quantities of plankton through the mouth to obtain nutrition.

Reproduction and Lifespan

On average, anemonefish live for 6 to 10 years.

All clownfish are born male. They can change sex to become female later in life, depending on their social structure

For example, these fish live in groups, or schools, that are led by one dominant female. The second-largest fish becomes the dominant male, and the rest are smaller males. If something happens to the dominant female of the group, the dominant male switches to become female. Two males can also become mating partners; in that case, the larger, more dominant one becomes a female.

These social fish are monogamous. Before spawning, the male anemonefish prepares the nest, usually found within an anemone or on a rock nearby. He then courts a female by extending his fins, chasing, and biting at her. The female then passes over the nesting site multiple times, laying anywhere from 100 to 1,000 eggs. The male then passes over, releasing sperm to fertilize the eggs.

The female clownfish then leaves, and the male tends to the nest. The larvae hatch six to eight days later and float away. After spending about 10 days adrift, they settle onto the bottom of the coral reef before seeking a host anemone. They transform from being clear and translucent to having their distinctive orange coloring and markings during this time.