Acanthurus tristis Randall, 1993
Indian Ocean mimic surgeonfish
photo by Randall, J.E.

Family:  Acanthuridae (Surgeonfishes, tangs, unicornfishes), subfamily: Acanthurinae
Max. size:  25 cm TL (male/unsexed)
Environment:  reef-associated; marine; depth range 2 - 30 m
Distribution:  Indian Ocean: Bay of Bengal (Ref. 8940) and the Andaman Sea west to Maldives and Chagos Archipelago, and east to islands of southern Indonesia at least to Bali.
Diagnosis:  Dorsal spines (total): 8-8; Dorsal soft rays (total): 23-33; Anal spines: 3-3; Anal soft rays: 22-29. Margin of caudal fin narrow and white. No orange area behind gill opening and extending ventrally behind base of pectoral fins (juveniles mimic the angelfish Centropyge eibli) (Ref 9808). Description: Characterized further by having dark band from chin to upper edge of gill cover; white margin on caudal fin; length of caudal spine 2.5-4.7 in head length; greatest depth of body 1.8-2.0 in SL (Ref. 90102).
Biology:  Occurs in shallow lagoon and seaward reefs, in areas of mixed coral, rock or sand. Juveniles mimic the cryptic Centropyge eibli (Ref. 9710, 48637).
IUCN Red List Status: Least Concern (LC); Date assessed: 04 May 2010 Ref. (130435)
Threat to humans:  harmless


Source and more info: www.fishbase.org. For personal, classroom, and other internal use only. Not for publication.