Naso caesius Randall & Bell, 1992
Gray unicornfish
photo by Randall, J.E.

Family:  Acanthuridae (Surgeonfishes, tangs, unicornfishes), subfamily: Nasinae
Max. size:  45.6 cm SL (male/unsexed)
Environment:  reef-associated; marine; depth range 15 - 50 m
Distribution:  Pacific Ocean: Northern Marianas, Marshall Islands, Hawaiian Islands, Pitcairn group, Society Islands (French Polynesia), Australia and New Caledonia.
Diagnosis:  Dorsal spines (total): 6-7; Dorsal soft rays (total): 27-30; Anal spines: 2-2; Anal soft rays: 28-31. Bluish grey to grey-brown, capable of displaying a colour pattern of vertically elongate blotches (lighter or darker than ground colour) on side and upper part of body. Opercular and preopercular margins not dark brown. Caudal fin uniform in colour. Gill rakers on lower limb of gill arches entirely pale. Edge of lower lip not white (Ref 9808). Description: Characterized further by absence of horn or protuberance; caudal peduncle with pair of bony plates, blade-like keels not pointed; greatest depth of body 2.5-3.0 in SL (Ref. 90102).
Biology:  Benthopelagic over coral and rock (Ref. 58302). Occurs singly or in aggregations along clear seaward and outer lagoon reefs and channels (Ref. 37816). Feeds in midwater on zooplankton (Ref. 90102).
IUCN Red List Status: Least Concern (LC); Date assessed: 06 May 2010 Ref. (124695)
Threat to humans:  harmless
Country info:   

Entered by: Casal, Christine Marie V. - 08.11.95
Modified by: Valdestamon, Roxanne Rei - 30.04.13

Source and more info: For personal, classroom, and other internal use only. Not for publication.

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