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Naso hexacanthus (Bleeker, 1855)
Blue-tail Unicorn; Sleek Unicorn; Priodon hexacanthus Bleeker, 1855

Life   Vertebrata   Fish   Acanthuridae   Naso

Naso hexacanthus
© Copyright John Rangall, 2006 · 0
Naso hexacanthus

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Main identification features
  • no horn
  • blue-grey back, yellowish below
  • tail base: 2 keels
Body elongate, oval, strongly compressed; no horn on forehead, upper and lower body profiles symmetrically convex; teeth small, conical, with tips slightly depressed, smooth or with slight denticulations; 2 pairs of large cutting keels on plates on narrow tail base; pelvics I, 3; dorsal VI, 27-29; anal II, 27-30; pectoral 17-18 rays; tail margin straight, without filaments, concave in juveniles.

Blue-grey to brown above, shading to yellowish brown ventrally; rear margin of operculum and preopercle often dark; tongue black; dorsal olive; tail blue grey, broad olive margin; anal and pelvics yellow-olive; pectoral blue grey, dark margin; courting males can abruptly develop upper head and upper front of body blue, blue lines and spots on front flank.

Size: 75 cm.

Habitat: reefs and rocky shores; juveniles on reef crests in sheltered habitats; adults in midwater around exposed reef fronts.

Depth: 0-150 m; juveniles usually 5-35 m; adults usually 10-40 m.

An Indo-Pacific species recorded as a vagrant at Clipperton and Cocos Islands.

Abundance: Common.
Cites: Not listed.
Climate Zone: Equatorial (Costa Rica to Ecuador + Galapagos, Clipperton, Cocos, Malpelo).
Depth Range Max: 150 m.
Depth Range Min: 0 m.
Diet: pelagic fish larvae; zooplankton; benthic microalgae.
Eastern Pacific Range: Northern limit=11; Southern limit=6; Western limit=-110; Eastern limit=-87; Latitudinal range=5; Longitudinal range=23.
Egg Type: Pelagic; Pelagic larva.
Feeding Group: Omnivore; Planktivore.
FishBase Habitat: Reef Associated.
Global Endemism: All Pacific (West + Central + East); Indo-Pacific only (Indian + Pacific Oceans); TEP non-endemic; "Transpacific" (East + Central &/or West Pacific); All species.
Habitat: Corals; Reef associated (reef + edges-water column & soft bottom); Rocks; Reef (rock &/or coral); Reef only.
Inshore Offshore: Inshore; Inshore Only.
IUCN Red List: Not evaluated / Listed.
Length Max: 75 cm.
Regional Endemism: Island (s) only; Island (s); Tropical Eastern Pacific (TEP) non-endemic; Eastern Pacific non-endemic; All species.
Residency: Vagrant.
Salinity: Marine; Marine Only.
Water Column Position: Bottom; Mid Water; Near Bottom; Bottom + water column;

Scientific source:

Links to other sites

  • Allen , G.R. and Robertson, D.R., 1997., An Annotated Checklist of the fishes of Clipperton Atoll, Tropical Eastern Pacific., Revista de Biologia Tropical, 45:813-843.
  • Bleeker,., 1855., Zesde bijdrage tot de kennis der ichthyologische fauna van Amboina., Natuurkd. Tijdschr. Neder. Indië, 8:391-434.
  • Robertson , D.R. and Allen, G.A., 1996., Zoogeography of the shorefish fauna of Clipperton Atoll., Coral Reefs, 15:121-131.
  • Smith , M. M. and Heemstra, P., 1986., Smith's Sea Fishes. Johannesburg: Macmillan South Africa. 1047 pp., Macmillan South Africa:1047pp.


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Following modified from Australian Faunal Directory
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http://biodiversity.org.au/afd/taxa/f095717e-3693-4fa2-b60c-fc3758244be4 ---> https://biodiversity.org.au/afd/taxa/f095717e-3693-4fa2-b60c-fc3758244be4
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Following modified from Taiwan Biodiversity National Information Network
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Following modified from FishBase
   Top | See original

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Updated: 2020-10-01 12:12:07 gmt
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