''Genicanthus personatus'' the masked angelfish, is a species of marine ray-finned fish, a marine angelfish belonging to the family Pomacanthidae. 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 ...

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

Description

''Genicanthus personatus'' is largely a brilliant white colour at all ages. The juveniles have an area of black colour which covers most of the head. As the fish grows this breaks up starting with the lips which turn bluish white and their

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 se ...

s begin to darken to become black. This species, like all marine angelfish, is a sequential

protogynous 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, ...

and the younger sexually mature adults are all females. The black on the head reduces in extent. The black eventually only surrounds the eyes, is on the chin and along the edge of the operculum and its operculum spine. They also have yellow

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s. Once they reach a length of they may change sex to males. When they do so, they develop a vivid orange yellow pigmentation on the

pectoral 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 and on the whole face as well as on the margins of its

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

anal Anal may refer to: Related to the anus *Related to the anus of animals: ** Anal fin, in fish anatomy ** Anal vein, in insect anatomy ** Anal scale, in reptile anatomy *Related to the human anus: ** Anal sex, a type of sexual activity involvin ...

and pelvic fins. The males develop long filamentous extensions to the caudal fin lobes. This species attains a maximum total length of .

Distribution

''Genicanthus personatus'' is endemic to the Hawaiian Islands, here it is more numerous in the northwestern islands.

Habitat and biology

''Genicanthus personatus'' is found at depths between where it occurs over rocky reefs and on the outer slopes of reefs. The diet of this species comprises green algae in the genus Codium as well as planktonic organisms and the eggs of fishes. Like all other angelfish the masked angelfish is a

, with all individuals being female initially and the dominant ones changing to males.

Systematics

''Genicanthus personatus'' was first formally described in 1975 by the American

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish ( Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of Octobe ...

John Ernest Randall (1924–2020) with the type locality given as

Honolulu Honolulu (; ) is the capital and largest city of the U.S. state of Hawaii, which is in the Pacific Ocean. It is an unincorporated county seat of the consolidated City and County of Honolulu, situated along the southeast coast of the island ...

Oahu Oahu () (Hawaiian language, Hawaiian: ''Oʻahu'' ()), also known as "The Gathering place#Island of Oʻahu as The Gathering Place, Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over t ...

. The specific name ''personatus'' means “masked”.

Utilisation

''Genicanthus personatus'' is very rare in the aquarium traded down commands high prices. It has been bred in captivity.

References

bishopmuseum.org
{{Taxonbar, from=Q2110136 Fish of Hawaii personatus Fish described in 1975