A beautiful fish of tropical reefs in the Indian Ocean, the sohal surgeonfish (Acanthurus sohal) is vividly coloured with striking blue and white stripes stretching along the body and jet black fins with yellow margins (3). This attractive fish is dark blue on the upperside, fading to silver on the sides, and whitish on the underside (4)(5). There are narrow blackish stripes on the head above the eyes, faint grey lines below the head and chest, and patches of orange beneath the pectoral fins and around the razor-sharp, long, slender tail spine (4)(5)(6). This spine normally sits flattened in a groove, but when the fish is disturbed or threatened this formidable weapon is rapidly erected and can be used to inflict slashing wounds on other fish (6). The distinctive sohal surgeonfish also has a deep, elongated, flattened body, with the eyes positioned high on the head, and a well-defined, concave tail fin with long, elaborate lobes, which are black with a vibrant blue edge and a large diffuse brown area in the centre (2)(4)(5). The mouth is small, but armed with an impressive array of small, sharp teeth which are used to rasp algae on rocks (2)(6).
Also known as
Arabian surgeonfish, Red Sea clown surgeonfish, Red Sea surgeonfish, sohal, sohal tang.
An inquisitive and bold fish, the sohal surgeonfish aggressively defends a territory from other fish (3). Like other surgeonfishes, it has a sharp spine at the base of its tail and can use this to slash at other fish by rapidly sweeping its tail to the side (2). It feeds on various kinds of algae which it scrapes off rocks with its sharp teeth (2).
Little else is known of the sohal surgeonfish’s biology, but like other surgeonfish it probably breeds in aggregations over relatively deep, open water, the timing of which is determined by the lunar cycle (2)(3).
There are no known major threats to the sohal surgeonfish, but as a species that inhabits reefs, it could be adversely affected by a number of activities that degrade or destroy coral reef habitats, such as pollution and irresponsible development, as well as global climate change (7)(8). It is also captured across its range in artisanal fisheries (2).
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