Bluespine Unicornfish, Naso unicornis (Forsskål 1775)

Other Names: Blue-spine Unicorn, Blue-spine Unicornfish, Blue-spined Unicorn, Brown Unicornfish, Brown Unicorn-fish, Longnose Unicornfish, Spotted Unicornfish

A Bluespine Unicornfish, Naso unicornis, in the Red Sea. Source: Rick Stuart-Smith / Reef Life Survey. License: CC BY Attribution

A large greenish-grey surgeonfish with a pair of bright blue plates on the caudal peduncle bearing knife-like spines, yellowish dorsal anal fins with narrow blue margins, and a relatively short horn on the forehead.

Video of a Bluespine Unicornfish at Dahab, Red Sea, Egypt

Cite this page as:
Bray, D.J. 2019, Naso unicornis in Fishes of Australia, accessed 16 Apr 2024,

Bluespine Unicornfish, Naso unicornis (Forsskål 1775)

More Info


Rottnest Island to Beagle Reef and offshore reefs of Western Australia, Ashmore and Cartier Islands, Timor Sea, and the far northern Great Barrier Reef and reefs in the Coral Sea, to central New South Wales, with juveniles to southern NSW; also Cocos (Keeling) Islands and Christmas Island in the eastern Indian Ocean, and Middleton and Elizabeth Reefs, Lord Howe Island and Norfolk Island in the Tasman Sea. Elsewhere the species occurs in the tropical, Indo-west-central Pacific: from the Red Sea and East Africa, to Hawaii, and the Line and Pitcairn islands.
Inhabits lagoons and outer reefs, grazing on macroalgae.


Dorsal fin VI, 27-30; Anal fin II, 27-30; Pectoral fin 17-18.
Body depth 2.0-2.6 in SL; horn on forehead not projecting forward of mouth; pair of bony plates on caudal peduncle, each with a forward-projecting spine.


Herbivore - feed on macroalgae.


An important food fish in parts of its range.


When courting females, males may perform displays associated with rapid changes in the colours of the horn on the head and other body parts, highlighting the protuberance by colour contrast.


Species Citation

Chaetodon unicornis Forsskål 1775, Descriptiones Animalium: 63. Type locality: Djedda, Red Sea.


Bray, D.J. 2019


Atlas of Living Australia

Bluespine Unicornfish, Naso unicornis (Forsskål 1775)


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Quick Facts

CAAB Code:37437031

Conservation:IUCN Least Concern

Depth:1-80 m

Habitat:Reef associated

Max Size:70 cm FL

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Species Maps

CAAB distribution map