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. Indiƫ 8: 393, 421. Type locality: Ambon (as Amboina), Indonesia.

Author

Bray, D.J. 2022

Resources

Sleek Unicornfish, Naso hexacanthus (Bleeker 1855)

References


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. 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.

Choat, J.H., Clements, K.D. & Robbins, W.D. 2002. The trophic status of herbivorous fishes on coral reefs. 1. Dietary analyses. Marine Biology 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. Marine Biology 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

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


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. 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

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