Actinopteri (ray-finned fishes) > Acanthuriformes
(Surgeonfishes) > Acanthuridae
(Surgeonfishes, tangs, unicornfishes) > Nasinae
Etymology: Naso: Latin, nasus = nose (Ref. 45335). More on author: Cuvier.
Environment: milieu / climate zone / depth range / distribution range
Marine; reef-associated; depth range 2 - 122 m (Ref. 58302), usually 4 - 46 m (Ref. 27115). Tropical; 24°C - 28°C (Ref. 27115); 29°N - 36°S, 26°E - 137°W (Ref. 57250)
Indo-Pacific: Red Sea and East Africa to the Hawaiian, Marquesas and Ducie islands, north to southern Japan, south to Lord Howe Island (Ref. 1602); exxcluding Oman and Persian Gulf (Ref. 86689). Eastern Central Pacific: Galápagos Islands.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 60.0 cm TL male/unsexed; (Ref. 9808)
soft rays: 27 - 30. This species is distinguished by the following characters: body moderately deep and compressed, its depth 2.6 to 3 times in standard length (SL) (reported greatest depth of body in subadults at 2.3 in SL, Ref. 90102); dorsal profile of body uniformly convex; adults with a median, broad-based, tapering, horn-like projection extending directly anteriorly from snout at level of lower part of eye to more than 1/2 head length in front of mouth (first developing as a bump on forehead of young of about 10 cm SL; dorsal profile of snout from upper lip to base of horn very short, curved, and nearly vertical; mouth small; teeth small, spatulate, with denticulate edges, about 50 in each jaw; a continuous unnotched D VI,27-29; A II,27-30; pectoral-fin rays 15-17; pelvic fins I,3; caudal fin slightly rounded, without a filament from each corner; 2 bony plates on each side of caudal peduncle, developing moderate keels with age; colour of body olivaceous grey-brown to light grey, usually with vertical dark brown lines on body which break into small spots dorsally and ventrally; some individuals only with small dark spots; head with small dark brown spots or short irregular lines which become long and oblique on horn (dark markings on one pale phase may be faint or absent; in another phase the anterior third of the body may be distinctly paler than the rest); caudal fin whitish with a large diffuse dark blotch centrobasally in fin (Ref. 9808).
Inhabit mid-waters along steep outer lagoon and seaward reef drop-offs. Also found along rocky shores (Ref. 30573, 48637). Benthopelagic (Ref. 58302). Usually in small groups but form large schools in oceanic locations or on reefs subject to strong currents (Ref. 48637). Juveniles and subadults feed on benthic algae; adults feed on zooplankton. Pair spawning has been observed. Caught with nets (Ref. 30573).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Probably spawn in pairs (Ref. 240).
Myers, R.F., 1991. Micronesian reef fishes. Second Ed. Coral Graphics, Barrigada, Guam. 298 p. (Ref. 1602)
IUCN Red List Status (Ref. 123251)
CITES (Ref. 123416)
Threat to humans
Reports of ciguatera poisoning (Ref. 30298)
Fisheries: commercial; aquarium: commercial
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates based on models
Preferred temperature (Ref. 115969
): 24.3 - 29, mean 27.8 °C (based on 1558 cells).
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01950 (0.01247 - 0.03050), b=3.02 (2.89 - 3.15), in cm total length, based on LWR estimates for this species & Genus-body shape (Ref. 93245
Trophic level (Ref. 69278
): 2.2 ±0.15 se; based on food items.
Generation time: 2.7 ( na - na) years. Estimated as median ln(3)/K based on 1 growth studies.
Resilience (Ref. 120179
): Medium, minimum population doubling time 1.4 - 4.4 years (K=0.402; Tmax=25).
Vulnerability (Ref. 59153
): Low to moderate vulnerability (33 of 100) .