Bluespine Unicornfish

Max length : 70.0 cm FL male/unsexed; common length : 50.0 cm TL male/unsexed

Family	Acanthuridae
Description	Surgeonfishes, tangs, unicornfishes
Environment	Marine
Etymology	Greek, akantha = thorn + oura = tail
Genus	6
No. of Species	82
Order	Perciformes
Class	Actinopterygii
Reproductive Guild	Nonguarders
Distribution	Circumtropical, especially around coral reefs; five species in the Atlantic, the remaining in the Pacific and Indian oceans. All have a deep compressed body with the eye high on the head and a long preorbital bone. Single unnotched dorsal fin with 4-9 spines and 19-31 rays; anal fin with 2 (only Naso) or 3 spines and 19-36 rays; pelvic fins with 1 spine and 3 (Naso and Paracanthurus) or 5 rays. Very small ctenoid scales. A small terminal mouth with a single row of close-set teeth. Most surgeon fishes graze on benthic algae and have a long intestine; some feed mainly on zooplankton or detritus. Surgeon fishes are able to slash other fishes with their sharp caudal spines by a rapid side sweep of the tail. Pelagic spawners. Many species have bright colors and are popular aquarium fishes.

Kala

Inhabit channels, moats, lagoon and seaward reefs with strong surge. Benthopelagic. Typically occurring in small groups. Sometimes solitary. Juveniles in shallow protected bays and harbours. Mainly diurnal, feed on coarse leafy brown algae like Sargassum. Pair-spawning has been observed

Dorsal spines (total): 6; Dorsal soft rays (total): 27-30; Anal spines: 2; Anal soft rays: 27 - 30. This species is characterized by the following: body depth 1.8 (in subadults) - 2.6 (adults) in SL; presence of a tapering body horn in adults projecting anteriorly at level of eye but not extending in front of mouth (horn first as a bump on forehead at a length of about 12 cm); dorsal profile from snout to horn straight, angle of about 45°; 2 peduncular plates with well-developed forward-curving knife-like spines; emarginate caudal fin when young, truncate with filamentous lobes in adult; olivaceous with blue peduncular plates and spines; dorsal and anal fins yellowish with narrow blue stripes

Spawn in pairs

Summary of Distribution: Indo-Pacific: Red Sea and East Africa to the Hawaiian, Marquesas and Tuamoto islands, north to southern Japan, south to Lord Howe and Rapa islands. Presence in Somalia to be confirmed
Note: Distribution range colors indicate degree of suitability of habitat which can be interpreted as probabilities of occurrence (fishbase.org)