12782 Acanthurus tristis Randall, 1993 Acanthuridae Surgeonfishes, tangs, unicornfishes Acanthurinae Acanthuriformes Teleostei Indian Ocean mimic surgeonfish 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.