''Amphiprion chagosensis'', the Chagos anemonefish, is a

marine fish Saltwater fish, also called marine fish or sea fish, are fish that live in seawater. Saltwater fish can swim and live alone or in a large group called a school. Saltwater fish are very commonly kept in aquariums for entertainment. Many saltwater f ...

belonging to the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Pomacentridae, the

clownfish Clownfish or anemonefish are fishes from the subfamily Amphiprioninae in the family Pomacentridae. Thirty species of clownfish are recognized: one in the genus ''Premnas'', while the remaining are in the genus ''Amphiprion''. In the wild, th ...

es and

damselfish Damselfish are those within the subfamilies Abudefdufinae, Chrominae, Lepidozyginae, Pomacentrinae, and Stegastenae within the family Pomacentridae. Most species within this group are relatively small, with the largest species being about 30 ...

es. It is named for the

Chagos Archipelago The Chagos Archipelago () or Chagos Islands (formerly the Bassas de Chagas, and later the Oil Islands) is a group of seven atolls comprising more than 60 islands in the Indian Ocean about 500 kilometres (310 mi) south of the Maldives archi ...

in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...

and it is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the archipelago. The original specimens were collected at

Diego Garcia Diego Garcia is an island of the British Indian Ocean Territory, a disputed overseas territory of the United Kingdom. It is a militarised atoll just south of the equator in the central Indian Ocean, and the largest of the 60 small islands o ...

Atoll, Chagos Archipelago.

Characteristics of anemonefish

Clownfish or anemonefish are

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

es that, in the wild, form

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

mutualisms with

sea anemone Sea anemones are a group of predation, predatory marine invertebrates of the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemones are classifi ...

s 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. 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 Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...

and

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

oceans and the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

in sheltered

reef A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock out ...

s or in shallow

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') a ...

s. In a group of clownfish, there is a strict

dominance hierarchy In biology, a dominance hierarchy (formerly and colloquially called a pecking order) is a type of social hierarchy that arises when members of animal social animal , social groups interact, creating a ranking system. A dominant higher-ranking i ...

. 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 External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. It is contrasted with internal fertilization, in which sperm are introduced via insemination and then ...

. Clownfish are sequential hermaphrodites, meaning that they develop into males first, and when they mature, they become females.

Description

Adults are light brown with two white bars with dark edging encircling the body. All fins are dusky brown. They have 10-11 dorsal spines, 2 anal spines, 15-17 dorsal soft rays and 13-14 anal soft rays. They reach a maximum length of .

Color variations

None known.

Similar species

The Chagos anemonefish is mainly distinguished by location, with similar species mostly having a geographic separation, with '' A. akindynos'' being found on the

Great Barrier Reef The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, ...

and

Coral Sea The Coral Sea () is a marginal sea of the South Pacific off the northeast coast of Australia, and classified as an interim Australian bioregion. The Coral Sea extends down the Australian northeast coast. Most of it is protected by the Fre ...

and '' A. allardi'' in

East Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa: Due to the historical ...

. '' A. bicinctus'' is found in the

but has an overlapping distribution at Chagos. ''A. chagosensis'' has a narrower headbar and a whiteish caudal fin. Specimens can also be distinguished by differences in predorsal scalation. Image:A, chagosensis 2.jpg, A. chagosensis, with Macrodactyla doreensis, long tentacle anemone Image:Amphiprion akindynos RLS.jpg, '' A. akindynos'' (Barrier Reef anemonefish) Image:Amphiprion allardi in the UShaka Sea World 1038.jpg, '' A. allardi'' (Allard's anemonefish). Image:Amphiprion bicinctus by Patryk Krzyzak.jpg, '' A. bicinctus'' (Two-band anemonefish)

Distribution and habitat

''A. chagosensis'' is found only in the Chagos Archipelago.

Host anemones

Little is known about the specific host anemone species with which ''A. chagosensis'' associates, however it has been photographed in association with: *''

Entacmaea quadricolor Bubble-tip anemone (''Entacmaea quadricolor'') is a species of sea anemone in the family Actiniidae. Like several anemone species, ''E. quadricolor'' can support several anemonefish species, and displays two growth types based on where they live ...

'' Bubble-tip anemone *''

Heteractis magnifica ''Heteractis magnifica'', also known by the common names magnificent sea anemone or Ritteri anemone, is a species of sea anemone belonging to the Stichodactylidae family native to the Indo-Pacific area. Description The magnificent sea anemone is ...

'' magnificent sea anemone *''

Macrodactyla doreensis ''Macrodactyla doreensis'', common names long tentacle anemone and corkscrew tentacle sea anemone, is a species of sea anemone in the family (biology), family Actiniidae. Description ''Macrodactyla doreensis'' has relatively few tentacles. They ...

'' long tentacle anemone *'' Stichodactyla mertensii'' Mertens' carpet sea anemone

References

External links

* * {{Taxonbar, from=Q1058817 chagosensis Fish described in 1972