Black and Brown Surgeonfish

Max length : 21.0 cm TL male/unsexed

Family	Acanthuridae
Description	Surgeonfishes, tangs, unicornfishes
Environment	Marine
Etymology	Greek, akantha = thorn + oura = tail
Genus	6
No. of Species	82
Order	Perciformes
Class	Actinopterygii
Reproductive Guild	Nonguarders
Distribution	Circumtropical, especially around coral reefs; five species in the Atlantic, the remaining in the Pacific and Indian oceans. All have a deep compressed body with the eye high on the head and a long preorbital bone. Single unnotched dorsal fin with 4-9 spines and 19-31 rays; anal fin with 2 (only Naso) or 3 spines and 19-36 rays; pelvic fins with 1 spine and 3 (Naso and Paracanthurus) or 5 rays. Very small ctenoid scales. A small terminal mouth with a single row of close-set teeth. Most surgeon fishes graze on benthic algae and have a long intestine; some feed mainly on zooplankton or detritus. Surgeon fishes are able to slash other fishes with their sharp caudal spines by a rapid side sweep of the tail. Pelagic spawners. Many species have bright colors and are popular aquarium fishes.

Found on hard substrates of shallow lagoon and seaward reefs from the lower surge zone to a depth of more than 15 m. Benthopelagic. Feed on filamentous algae. Form spawning aggregations. Adults usually in small groups, but form large schools in some oceanic locations. Juveniles are often seen in mixed species aggregations. Species at the bottom of the 'pecking order' among surgeon fishes, and as a result employs the strategy of feeding in large schools that overwhelm the territorial defenses of other herbivores. Caught with nets. Can be eaten both raw and cooked. Maximum depth reported at 25m

Dorsal spines (total): 9; Dorsal soft rays (total): 24-27; Anal spines: 3; Anal soft rays: 22 - 24. Brown in color when preserved; with or without fine bluish gray longitudinal lines on body; pale pectoral fins with upper edge narrowly black; pelvic fins brown. Lips blackish brown; median upper teeth tend to be pointed. Dorsal fin base with a prominent black spot larger than 1/2 eye diameter; a smaller spot on base of anal fin. Groove of caudal spine encircled with a narrow black margin. Gill rakers on anterior row:20-24; on posterior row:18-23.

Form spawning aggregations

Summary of Distribution: Indo-Pacific: Red Sea south to Transkei, South Africa (Ref. 3145) and east to the Hawaiian and Tuamoto islands, north to southern Japan, south to the southern Great Barrier Reef, New Caledonia, and Rapa (Austral Islands).
Note: Distribution range colors indicate degree of suitability of habitat which can be interpreted as probabilities of occurrence (fishbase.org)