Sleek Unicornfish, Naso hexacanthus (Bleeker 1855)

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

Sleek Unicornfish, Naso hexacanthus, on Day Reef near Lizard Island, Great Barrier Reef, Queensland. Source: Anne Hoggett, Lizard Island Field Guide / http://lifg.australianmuseum.net.au/. License: CC by Attribution

Summary:

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:

Bray, D.J. 2022, Naso hexacanthus in Fishes of Australia, accessed 19 Apr 2024, https://fishesofaustralia.net.au/Home/species/2196

Sleek Unicornfish, Naso hexacanthus (Bleeker 1855)

More Info

Distribution	Offshore reefs of Western Australia, Ashmore Reef in the Timor Sea, and the northern Great Barrier Reef to Moreton Bay, Queensland, also reefs in the Coral Sea; also Cocos (Keeling) Islands and Christmas Island in the eastern Indian Ocean, and the Lord Howe Province in the Tasman Sea. Elsewhere the species is widespread in the Red Sea and tropical, Indo-west Pacific. Inhabits seaward reefs, and large schools are usually seen feeding in the water column near drop-offs.
Feeding	Feeds in midwater on zooplankton.
Remarks	The species is easily confused with Naso caesius and some records of Naso hexacanthus may be misidentifications of N. caesius.
Similar Species	The similar Silverblotched Unicornfish, Naso caesius, differs in having smaller bladelike caudal spines that do not become sharply pointed and antrorse in large males, a pale tongue (vs. black in N. hexacanthus), overall bluish grey (vs. yellowish ventrally in N. hexacanthus), in lacking dark borders on the opercle and preopercle (present in N. hexacanthus).
Etymology	The specific name hexacanthus is from the Latin hexa (= six) and akanthus (= horn, point, thorn), in reference to the six dorsal-fin spines of this species.
Species Citation	Priodon hexacanthus Bleeker, 1855, Natuurwetensch. Tijdschr. Nederland. Indië 8: 393, 421. Type locality: Ambon (as Amboina), Indonesia.
Author	Bray, D.J. 2022
Resources	Atlas of Living Australia Australian Faunal Directory Catalog of Fishes

Sleek Unicornfish, Naso hexacanthus (Bleeker 1855)

References

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

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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 Indië 8: 391-434. See ref at BHL

Choat, J.H. & Axe, L.M. 1996. Growth and longevity in acanthurid fishes: an analysis of otolith increments. Marine Ecology Progress Series 134: 15-26.

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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

Francis, M. 2019. Checklist of the coastal fishes of Lord Howe, Norfolk and Kermadec Islands, southwest Pacific Ocean Version: 2019.1 https://doi.org/10.6084/m9.figshare.c.4428305

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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.

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

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