The three-band anemonefish (''Amphiprion tricinctus'') is a species of

anemonefish 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, the ...

endemic to the

Marshall Islands The Marshall Islands ( mh, Ṃajeḷ), officially the Republic of the Marshall Islands ( mh, Aolepān Aorōkin Ṃajeḷ),'' () is an independent island country and microstate near the Equator in the Pacific Ocean, slightly west of the Internati ...

in the western part of the

Pacific Ocean 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 contine ...

. Like all anemonefishes, it forms a symbiotic mutualism with sea anemones and is unaffected by the stinging tentacles of its host. It is a

sequential hermaphrodite Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, ...

with a strict size-based

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 groups interact, creating a ranking system. A dominant higher-ranking individual is so ...

; the female is largest, the breeding male is second largest, and the male nonbreeders get progressively smaller as the hierarchy descends. They exhibit

protandry Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, ...

, meaning the breeding male changes to female if the sole breeding female dies, with the largest nonbreeder becoming the breeding male. The fish's natural diet includes

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

Description

The body of ''A. tricinctus'' is yellow-orange at the snout, belly, and pelvic and anal fins, tending to dark brown or black at the tail. As the common name suggests, as an adult it has three white bands or bars. They can grow to be about long

Color variations

As ''A. tricinctus'' is endemic to the Marshall Islands, no geographic variation is seen, bute variations to the proportions of orange and black occur, from predominately orange through to predominantly black and the occasional aberrant coloration. Fish living with the host anemone''

Stichodactyla mertensii ''Stichodactyla mertensii'', commonly known as Mertens' carpet sea anemone, is a species of sea anemones in the family Stichodactylidae. It is regarded as the largest sea anemone with a diameter of over , the next largest being '' Heteractis mag ...

'', Mertens' carpet sea anemone, are frequently black except for the snout and bars.

Similar species

Two other species have three body bars and a dark tail, ''A. chrysogaster'' and ''A. fuscocaudatus'', but the species are geographically separated. Three other species of anemonefish are found in the Marshall Islands, ''A. chrysopterus'', ''A. melanopus'', and ''A. perideraion''. These are easily distinguished from ''A. tricinctus'' as ''A. chrysopterus'' has two body bars and a whitish

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as s ...

, ''A. melanopus'' only has a head bar, and ''A. perideraion'' has a distinctive white stripe on the dorsal ridge.

Genetic analysis Genetic analysis is the overall process of studying and researching in fields of science that involve genetics and molecular biology. There are a number of applications that are developed from this research, and these are also considered parts of ...

has shown that ''A. tricinctus'' is closely related to ''A. clarkii'' and this clade is significantly different from the other species traditionally considered part of the ''A. clarkii ''complex.

Distribution and habitat

''A. tricinctus'' is endemic to the Marshall Islands in the western part of the Pacific Ocean and is found in lagoons and pinnacle and seaward reefs. Whilst it is most commonly found at depths of , it is occasionally found hosted by solitary specimens of ''

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 li ...

'' on seaward reef slopes in excess of deep.

Host anemones

The relationship between anemonefish and their host sea anemones is not random and instead is highly nested in structure. ''A. tricinctus'' is highly generalised, being hosted by eight of the 9 host anemones found in the Marshall Islands. ''A. tricinctus'' is generally said to be associated with these species of anemone: *''

'' bubble-tip anemone *''

Heteractis aurora ''Heteractis aurora'' is a species of sea anemone in the family Stichodactylidae. Taxonomy Common names for ''H. aurora'' include beaded sea anemone, aurora host anemone, sand anemone, carpet anemone, flat anemone, corn anemone, Ritteri anemo ...

'' beaded sea anemone (mostly juvenile) *''

Heteractis crispa The sebae anemone (''Heteractis crispa''), also known as leathery sea anemone, long tentacle anemone, or purple tip anemone, is a species of sea anemone belonging to the family Stichodactylidae and native to the Indo-Pacific area. It was first ...

'' sebae anemone *'' Stichodactyla haddoni'' *''

'' Mertens' carpet sea anemone Many locations in the Marshall Islands have not been scientifically surveyed, and ''A. tricinctus'' has been reported to be hosted by these species of anemone: *'' Heteractis magnifica'' magnificent sea anemone (rarely) *''

Heteractis malu ''Heteractis malu'', also known as the malu anemone, delicate sea anemone or white sand anemone, is a species of sea anemone in the family Stichodactylidae. Description This anemone has stout, sparse tentacles, almost always under 40mm in leng ...

'' delicate sea anemone (rarely) *''

Macrodactyla doreensis ''Macrodactyla doreensis'', common names long tentacle anemone and corkscrew tentacle sea anemone, is a species of sea anemone in the family Actiniidae. Description ''Macrodactyla doreensis'' has relatively few tentacles. They are all similar to ...

'' long-tentacle anemone

Conservation status

Anemonefish and their host anemones are found on coral reefs and face similar

environmental issues Environmental issues are effects of human activity on the biophysical environment, most often of which are harmful effects that cause environmental degradation. Environmental protection is the practice of protecting the natural environment on t ...

. Like

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secre ...

s, anemone's contain intracellular

endosymbiont An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "withi ...

zooxanthellae Zooxanthellae is a colloquial term for single-celled dinoflagellates that are able to live in symbiosis with diverse marine invertebrates including demosponges, corals, jellyfish, and nudibranchs. Most known zooxanthellae are in the genus '' ...

, and can suffer from

bleaching Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to ...

due to triggers such as increased water temperature or acidification. Characteristics known to elevate the risk of extinction are small geographic range, small local population, and extreme habitat specialisation. ''A. tricinctus'' is an endemic species, confined to the Marshall Islands, and this species' ability to use a variety of anemone hosts is thought to reduce the risk of extinction associated with specialisation.

In the aquarium

Specimens of ''A. tricinctus'' are occasionally for sale and the species has been bred in captivity.

Notes

References

External links

* * * {{Taxonbar, from=Q304249 Amphiprion Fish described in 1953