Clark's anemonefish (Amphiprion clarkii), also known as the yellowtail clownfish, is a marine fish belonging to the family Pomacentridae, the clownfishes and damselfishes. 28 species of anemonefish live within the Pomacentridae family (Steer P. 2012).

Characteristics of anemonefish

Clownfish or anemonefish are fishes<!--Please note that "fishes" is correct here. See wiki article Fish, subsection "Fish or fishes" --> that, in the wild, form symbiotic mutualisms with sea anemones and are unaffected by the stinging tentacles of the host anemone, see . The sea anemone protects the clownfish from predators, as well as providing food through the scraps left from the anemone's meals and occasional dead anemone tentacles. In return, the clownfish defends the anemone from its predators, and parasites. Anemonefish tend to have a life span of about 10-11 years when accounting for a predictable environment that does not experience much change in water temperature, increase in predation or habitat degradation (Lakshmi Sawitri). Clownfish are small-sized, , and depending on species, they are overall yellow, orange, or a reddish or blackish color, and many show white bars or patches. Within species there may be color variations, most commonly according to distribution, but also based on sex, age and host anemone. Clownfish are found in warmer waters of the Indian and Pacific oceans and the Red Sea in sheltered reefs or in shallow lagoons.

In a group of clownfish, there is a strict dominance hierarchy. The largest and most aggressive fish is female and is found at the top. Only two clownfish, a male and a female, in a group reproduce through external fertilization. Clownfish are sequential hermaphrodites, meaning that they develop into males first, and when they mature, they become females. They are not aggressive. When the egg production and spawning patterns of eight breeding pairs were observed in a coral reef off the coast of the Philippines, they preferred breeding in the colder months. A trend of a peak breeding season from November through May was seen; egg production increased up to the new moon and decreased after the full moon. This seasonality of spawning is comparable to other species of clownfish that live in temperate regions.

Description

thumb|left|melanistic variation with Stichodactyla haddoni

thumb|right|Clark's anemonefish in [[beaded sea anemone]]

thumb|left|Orange and black variation

thumb|right|Juvenile color variation

Clark's anemonefish is a small-sized fish which grows up to as a male and as a female. It is stocky, laterally compressed, and oval to rounded.

It is colorful, with vivid black, white, and yellow stripes, though the exact pattern shows considerable geographical variation. Usually it is black dorsally and orange-yellow ventrally, the black areas becoming wider with age. There are two vertical white bands, one behind the eye and one above the anus, and the caudal peduncle is white. The snout is orange or pinkish. The dorsal and caudal fins are orange-yellow, and the caudal fin is generally lighter in tone than the rest of the body, sometimes becoming whitish.

Color variations

Clark's anemonefish shows the greatest color variations of any anemonefish, with variations based on location, sex, age and host anemone. Adults in Vanuatu and New Caledonia are orange-yellow with two vertical white bands. Sex related color differences may be present, such as the female having a white caudal fin and the male having a yellow caudal fin. Juveniles are orange-yellow with vertical white bands.

Etymology

The specific name and the common name both honour the Scottish engraver John Heaviside Clark (1771–1836) who provided illustrations for Bennett's A Selection from the most remarkable and interesting Fishes found on the Coast of Ceylon, from drawings made in the Southern part of that Island.

References

Further reading

  • Steer, P. (2012) Amphiprion clarkii (black clownfish), Animal Diversity Web. Available at: https://animaldiversity.org/accounts/Amphiprion_clarkii/ (Accessed: 22 March 2025).
  • Moore, Billy, et al. "The Chromosome-Scale Genome Assembly of the Yellowtail Clownfish Amphiprion Clarkii Provides Insights into the Melanic Pigmentation of Anemonefish." G3: Genes | Genomes | Genetics, vol. 13, no. 3, Mar. 2023, pp. 1–12. EBSCOhost, https://doi-org.proxy-commonwealthu.klnpa.org/10.1093/g3journal/jkad002.