Paracanthurus hepatus

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Blue tang

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Perciformes
Family:	Acanthuridae
Genus:	Paracanthurus Bleeker, 1863
Species:	P. hepatus

Binomial name

Paracanthurus hepatus
(Linnaeus, 1766)

Paracanthurus hepatus, commonly known as the regal tang, is an average-sized colorful reef fish belonging to the family Acanthuridae. A popular fish in marine aquaria, it is the only member of the genus Paracanthurus.^[1]^[2] A number of common names has been attributed to the species, including but not limited to palette surgeonfish, blue tang, hippo tang, flagtail surgeonfish and the blue surgeonfish.

1 Anatomy and morphology
2 Distribution
3 Ecology and life history
4 Etymology and taxonomic history
5 Importance to humans
6 Conservation
7 In popular culture
8 Bibliography
9 References
10 External links

[edit] Anatomy and morphology

Paracanthurus hepatus has a royal blue body, yellow tail, and black 'palette' design. It grows to a maximum of generally 12.25 inches and is mostly herbivorous.^{[citation needed]}

[edit] Distribution

The species' range varies widely and can be found throughout the Indo-Pacific. It is seen around the reefs of East Africa, Hawaii, Japan, Samoa, New Caledonia, and the Great Barrier Reef.^{[citation needed]}

[edit] Ecology and life history

[edit] Feeding ecology

This fish feeds entirely on algae. It grazes algae from rocky areas and browses filamentous algae, thereby avoiding large quantities of calcareous materials. Other surgeonfishes have heavier-walled, gizzard-like stomachs, and are capable of handling ingested sand and other calcareous materials. Blue tangs are important in keeping algae populations under control, preventing algae from overgrowing and suffocating corals.^{[citation needed]}

[edit] Life history

Spawning occurs during late afternoon and evening hours. This event is indicated by a change in color from a uniform dark blue to a pale blue anterior and dark blue posterior. Males aggressively court female members of the school, leading to a quick upward spawning rush toward the surface of the water during which eggs and sperm are released. The eggs are small, approximately 0.8mm in diameter. The eggs are pelagic, each containing a single droplet of oil for flotation. The fertilized eggs hatch in twenty-four hours, revealing small, translucent larvae with silvery abdomens and rudimentary caudal spines. The newly hatched larvae are referred to as acronurus because they were once thought to represent a separate genus of fish, Acronurus. The acronurus is diamond-shaped and laterally compressed, with a head shaped like a triangle. It has large eyes and prominent pectoral fins, and vertical ridges on the body. The dorsal fins, anal fins, and scales begin to develop when the acronurus reaches 2-6 mm in length. The caudal spine does not appear until the acronurus reaches about 13 mm in length. Late post-acronurus drift inshore, where they metamorphose into juveniles. The acronurus lose their silver color and turn brown, and their profiles become round. The prominent dorsal and anal spines that are characteristic of the acronurus reduce, and the snout elongates. Complete metamorphosis takes about a week, after which two-inch long juveniles settle onto the bottom of a suitable inshore habitat.

[edit] Role in the ecosystem

Some known predators of Paracanthurus hepatus are tuna, jack, grouper and other large piscivores.^{[citation needed]}

[edit] Etymology and taxonomic history

Despite the similar name, the blue tang (Acanthurus coeruleus) which is found in the Caribbean is a completely different species than this one (Paracanthurus hepatus).

[edit] Importance to humans

P. hepatus in an aquarium.

The blue tang is of minor commercial fisheries importance, however it is occasionally utilized as a bait fish. The flesh has a strong odor and is not highly prized. This fish may cause ciguatera poisoning if consumed by humans. However, blue tangs are collected commercially for the aquarium trade. An unwary human who tries to handle the blue tang risks the chances of being badly cut by the caudal spine. These spines, on both sides of the caudal peduncle, are extended from the body when the fish becomes excited. The quick, thrashing sideways motion of the tail can produce deep wounds that result in swelling and discoloration, posing a high risk of infection. The pain can last for hours, until eventually subsiding into a dull ache. It is believed that some species of Acanthurus have venom glands while others do not. The spines are used only as a method of protection against aggressors.^{[citation needed]}

[edit] Conservation

The blue tang is currently not listed with the World Conservation Union (IUCN) Redlist and is considered to be in no immediate threat.^{[citation needed]}