Indian Ocean Mimic Surgeonfish, Acanthurus tristis Randall 1993

Other Names: Blackcheek Surgeonfish, Indian Mimic Surgeon, Indian Ocean Mimic Tang, Yellowspot Surgeonfish

An Indian Ocean Mimic Surgeonfish, Acanthurus tristis, in the Maldives. Source: John E. Randall / FishBase. License: CC by Attribution-NonCommercial

A yellowish-brown to dark brown surgeonfish with a broad dark band from the chin to the upper edge of the gill cover, a white band around the lower lip, a narrow white margin on the caudal fin, and a black margin around the spine on the caudal peduncle. The species lacks an orange patch behind gill opening.
The striped juveniles mimic Eibl's Angelfish, Centropyge eibli.

Cite this page as:
Bray, D.J. 2022, Acanthurus tristis in Fishes of Australia, accessed 17 Jul 2024,

Indian Ocean Mimic Surgeonfish, Acanthurus tristis Randall 1993

More Info


Australian territory of Christmas Island in the Eastern Indian Ocean. Elsewhere the species occurs in the eastern Indian Ocean - Chagos Archipelago and the Maldives to the Andaman Sea and southern Indonesia.
Inhabits lagoon and seaward reefs, usually in sheltered areas of mixed coral, rock, sand and rubble.


Dorsal in VIII, 233; Anal fin III,22-29; Pectoral fin 16; Caudal fin principal  rays 16, uppermost and lowermost unbranched; Procurrent caudal fin, upper and lower rays 4 (none segmented); Lateral-line ~78-88; Longitudinal scale series 92-96; Scales above lateral line to base of middle dorsal spines 8; Gill rakers anterior 22-26, posterior rakers 24-27; Vertebrae 9 + 13.

Body deep, compressed, depth 1.8–2.0 in SL; caudal spine 2.5–4.7 in HL; mouth  somewhat protruding; dorsal profile of snout convex; caudal fin of adults lunate.




Juveniles are collected for the aquarium trade.



Similar Species

The similar Mimic Surgeonfish, Acanthurus pyroferus, differs in having a black margin around eye, and orange patch above the pectoral-fin base, and yellow margin on caudal fin, and a white band around mouth. Juvenile A. pyroferus are entirely bright yellow.


The specific name is from the Latin tristis (= sad). The name dates to an unpublished manuscript and colour painting by British army officer, artist and ornithologist Samuel R. Tickell, mentioned by Francis Day in 1888, who described color as “slate-gray and slightly cinereous along the back,” with an irregular black band extending from upper edge of orbit to base of pectoral fin (Scharpf 2021).

Species Citation

Acanthurus tristis Randall 1993, Special Publication of the J.L.B. Smith Institute of Ichthyology Rhodes University 54: 4, figs 1-3. Type locality: Lively Rocks, Trincomalee, east coast of Sri Lanka, depth 10-12 m.


Bray, D.J. 2022


Atlas of Living Australia

Indian Ocean Mimic Surgeonfish, Acanthurus tristis Randall 1993


Abesamis, R., Clements, K.D., Choat, J.H., McIlwain, J., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Acanthurus tristis. The IUCN Red List of Threatened Species 2012: e.T177998A1516342. Downloaded on 07 June 2016

Allen, G.R. & Erdmann, M.V. 2012. Reef fishes of the East Indies. Perth : Tropical Reef Research 3 vols, 1260 pp.

Allen, G.R., Steene, R., Human, P. & Deloach, N. 2003. Reef Fish Identification Tropical Pacific. Jacksonville, Florida : New World Publications, Inc. 457 pp.

Day, F. 1888. Supplement to the Fishes of India. London : Williams & Norgate 779-816 pp., 7 figs.(listed in synonymy of Acanthurus tennentii as a form) See ref online

De Bruin, G.H.P., Russell, B.C. & Bogusch, A. 1995. FAO species identification field guide for fishery purposes. The marine fishery resources of Sri Lanka. Rome : FAO 400 pp.

Hobbs, J.-P.A., Ayling, A.M., Choat, J.H., Gilligan, J.J., McDonald, C.A., Neilson, J. & Newman, S.J. 2010. New records of marine fishes illustrate the biogeographic importance of Christmas Island, Indian Ocean. Zootaxa 2422: 63–68

Hobbs, J.-P.A., Newman, S.J., Mitsopoulos, G.E.A., Travers, M.J., Skepper, C.L., Gilligan, J.J., Allen, G.A., Choat, H.J. & Ayling, A.M. 2014. Checklist and new records of Christmas Island fishes: the influence of isolation, biogeography and habitat availability on species abundance and community composition. Raffles Bulletin of Zoology Suppl. 30: 184-202. See ref online

Kuiter, R.H. & Debelius, H. 2001. Surgeonfishes, Rabbitfishes and Their Relatives. A comprehensive guide to Acanthuroidei. Chorleywood, U.K. : TMC Publishing 208 pp.

Kuiter R.H. & Tonozuka, T. 2001. Indonesian Reef Fishes. Part 3. Jawfishes - Sunfishes, Opistognathidae - Molidae. Melbourne : Zoonetics pp. 623–893.

Myers, G.S. 1951. Some forgotten but available names for Indian fishes. Stanford Ichthyological Bulletin 4(1): 26.

Randall, J.E. 1993. Acanthurus tristis, a valid Indian ocean surgeonfish (Perciformes: Acanthuridae). Special Publication of the J.L.B. Smith Institute of Ichthyology Rhodes University 54: 1-8.

Randall, J.E. 2001. Surgeonfishes of Hawai'i and the world. Mutual Publishing and Bishop Museum Press, Hawai'i. 123 pp.

Scharpf, C. 2021. Order ACANTHURIFORMES (part 2) in The ETYFish Project Fish Name Etymology Database, accessed 31 Mar 2022,

Quick Facts

CAAB Code:37437051

Conservation:IUCN Least Concern

Depth:2-30 m

Fishing:Aquarium fish

Habitat:Reef associated

Max Size:25 cm TL

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Species Maps

CAAB distribution map