Sleek Unicornfish, Naso hexacanthus (Bleeker 1855)

Other Names: Blue-tail Unicorn, Sleek Unicorn, Thorpe's Unicornfish

A Sleek Unicornfish, Naso hexacanthus, at Barracuda Point, Pulau Sipadan, Sabah, Malaysia. Source: Bernard Dupont / Flickr. License: CC BY Attribution-ShareAlike

A brownish to bluish-grey surgeonfish becoming yellowish below, with a black margin on the cheek and gill cover. This species is easily confused with Naso caesius.

Video of a Sleek Unicornfish changing colour.

Cite this page as:
Dianne J. Bray, Naso hexacanthus in Fishes of Australia, accessed 02 Dec 2021,

Sleek Unicornfish, Naso hexacanthus (Bleeker 1855)

More Info


Offshore reefs of Western Australia: Rowley Shoals and Scott Reef, Ashmore Reef, Timor Sea, Christmas Island, Cocos (Keeling) Islands, and the northern Great Barrier Reef to Moreton Bay,
Queensland, also Coringa-Herald Cay and Lihou Reef, Coral Sea, and Lord Howe Island. The species occurs elsewhere in the tropical, Indo-Pacific.
Inhabits seaward reefs, and large schools are usually seen feeding in the water column near drop-offs.


Feeds in midwater on zooplankton.

Species Citation

Priodon hexacanthus Bleeker, 1855, Natuurwetensch. Tijdschr. Nederland. Indiƫ 8: 393, 421. Type locality: Ambon (as Amboina), Indonesia.


Dianne J. Bray


More information about Naso hexacanthus is available at:

Sleek Unicornfish, Naso hexacanthus (Bleeker 1855)


Allen, G.R. 1993. Fishes of Ashmore Reef and Cartier Island. Records of the Western Australian Museum, Supplement 44: 67-91.

Allen, G.R. 1997. Marine Fishes of Tropical Australia and South-east Asia. Perth : Western Australian Museum 292 pp. 106 pls.

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.C. & Orchard, M. 2007. Fishes of Christmas Island. Christmas Island : Christmas Island Natural History Association 2 edn, 284 pp.

Allen, G.R. & Russell, B.C. 1986. Part VII Fishes. pp. 79-103 in Berry, P.F. (ed.). Faunal Surveys of the Rowley Shoals, Scott Reef and Seringapatam Reef, northwestern Australia. Records of the Western Australian Museum, Supplement 25: 1-106.

Allen, G.R. & Smith-Vaniz, W.F. 1994. Fishes of Cocos (Keeling) Islands. Atoll Research Bulletin 412: 1-21.

Bleeker, P. 1855. Zesde bijdrage tot de kennis der ichthyologische fauna van Amboina. Natuurwetenschappelijk Tijdschrift voor Nederlandsch Indiƫ 8: 391-434.

Choat, J.H. & Axe, L.M. 1996. Growth and longevity in acanthurid fishes: an analysis of otolith increments. Mar. Ecol. Prog. Ser. 134: 15-26.

Choat, J.H., Clements, K.D. & Robbins, W.D. 2002. The trophic status of herbivorous fishes on coral reefs. 1. Dietary analyses. Mar. Biol. 140: 613-623.

Choat, J.H., McIlwain, J., Abesamis, R., Clements, K.D., Myers, R., Nanola, C., Rocha, L.A., Russell, B. & Stockwell, B. 2012. Naso hexacanthus. The IUCN Red List of Threatened Species. Version 2015.2. . Downloaded on 02 August 2015.

Choat, J.H. & Robertson, D.R, 2002. Age-based studies on coral reef fishes. pp. 57-80. In P.F. Sale (ed.) Coral reef fishes: dynamics and diversity in a complex ecosystem. Academic Press.

Dayton, C., Santayana, A.C. & Lacson, J.M. 1994. Genetic evidence for reproductive isolation of the recently described unicornfish Naso caesius and its sibling N. hexacanthus. Mar. Biol. 118: 551-554.

Francis, M. 1993. Checklist of the coastal fishes of Lord Howe, Norfolk, and Kermadec Islands, southwest Pacific Ocean. Pacific Science 47(2): 136-170 figs 1-2

Herre, A.W. 1927. Philippine surgeon fishes and moorish idols. Philippine Journal of Science 34(4): 403-478.

Hutchins, J.B. 2001. Biodiversity of shallow reef fish assemblages in Western Australia using a rapid censusing technique. Records of the Western Australian Museum 20: 247-270.

Johnson, J.W. 2010. Fishes of the Moreton Bay Marine Park and adjacent continental shelf waters, Queensland, Australia. pp. 299-353 in Davie, P.J.F. & Phillips, J.A. Proceedings of the Thirteenth International Marine Biological Workshop, The Marine Fauna and Flora of Moreton Bay. Memoirs of the Queensland Museum 54(3)

Kuiter, R.H. 1992. Tropical Reef-Fishes of the Western Pacific, Indonesia and Adjacent Waters. Jakarta : PT Gramedia Pustaka Utama 314 pp.

Kuiter, R.H. 1996. Guide to Sea Fishes of Australia. A comprehensive reference for divers and fishermen. Sydney, NSW, Australia : New Holland Publishers xvii, 434 pp.

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

Randall, J.E. 2001. Surgeonfishes of Hawai'i and the World. Honolulu : Mutual Publishing and Bishop Museum Press 125 pp.

Randall, J.E. 2001. Zanclidae, Acanthuridae. pp. 3651-3683 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 6 pp. 3381-4218.

Randall, J.E., Allen, G.R. & Steene, R. 1990. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 507 pp. figs.

Randall, J.E., Allen, G.R. & Steene, R. 1997. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 557 pp. figs.

Randall, J.E. & Bell, L.J. 1992. Naso caesius, a new acanthurid fish from the Central Pacific. Pac. Sci. 46(3): 344-352.

Russell, B.C. 1983. Annotated checklist of the coral reef fishes in the Capricorn-Bunker group, Great Barrier Reef, Australia. Great Barrier Reef Marine Park Authority. Special Publication Series 1: 1-184.

Russell, B.C., Larson, H.K., Hutchins, J.B. & Allen, G.R. 2005. Reef fishes of the Sahul Shelf. The Beagle, Records of the Museums and Art Galleries of the Northern Territory Supplement 1 2005: 83-105

Quick Facts

CAAB Code:37437028

Conservation:IUCN Least Concern

Depth:15-135 m

Habitat:Reef associated

Max Size:75 cm TL

Species Image Gallery

Species Maps

CAAB distribution map