''Heniochus pleurotaenia'', the phantom bannerfish, is a marine

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Chaetodontidae, native from the central

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

area.

Description

The phantom bannerfish is a small-sized fish that can reach a maximum length of 17 cm. Its body is compressed laterally, with the first rays of its

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

stretched in short white feather-like filaments. The background color is white with light chocolate to dark areas and a brown face mask covering the mouth, eyes and reaches to the base of the first rays of the dorsal fin. Its stretched snout has a small terminal protractile mouth. A little horn adorns the axis between the eyes and a rounded frontal outgrowth gives the impression that the profile of its face is concave. A second area forms an inverted "v" starting at the

ventral fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hind ...

s and ending on the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

. A third chocolate area runs from the last rays of the dorsal fin to the base of

caudal peduncle Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

. The phantom bannerfish can be confused with the very similar horned bannerfish, ''

Heniochus varius ''Heniochus varius'', the horned bannerfish or humphead bannerfish, is a species of marine ray-finned fish, a butterflyfish belonging to the family Chaetodontidae, native from the central Indo-Pacific area. Description The horned bannerfish is ...

'', which however does not have the reversed "v" pattern on its sides. Juveniles who lack the white insert can be distinguished by the shorter extension of the first rays of the dorsal fin.

Distribution and habitat

The phantom bannerfish is widespread throughout the tropical and subtropical waters of the central

from the

Maldives The Maldives, officially the Republic of Maldives, and historically known as the Maldive Islands, is an Archipelagic state, archipelagic country in South Asia located in the Indian Ocean. The Maldives is southwest of Sri Lanka and India, abou ...

to the western coast of

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

and from the south tip of

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

(

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

). It inhabits areas rich in coral in shallow lagoons and external reef slopes from the surface to a depth of 25 meters.

Habitat and biology

''Heniochus pleurotaenia'' is found in coral-rich areas of lagoons and seaward reefs where it occurs in pairs or aggregations. In Indonesia it is normally observed in pairs in coastal waters while in offshore areas these fish may aggregate to create schools and in some areas, such as the Maldives, they can be seen in very large schools. The phantom bannerfish are found at various depths, they are frequently on shallow reef crest which are subject to surge. They seem to prefer mixed algae and coral habitats down to depths of but are also found in deeper, offshore waters. This is an oviparous species which forms pairs during breeding.

Conservation status

In some geographic areas, the phantom bannerfish is occasionally harvested for the aquarium trade, however, the species does not currently appear threatened and is listed as

Least Concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

(LC) by the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

References

{{Taxonbar, from=Q2097482 pleurotaenia Fauna of the Maldives Fish of Sri Lanka Taxa named by Ernst Ahl Fish described in 1923