Appearance
Naso unicornfishes have a pointed snout and a rhomboidal or oval shaped body, with some species possessing a long protuberance on the forehead, typically present in both males and females. The caudal peduncle is slender and there are 1 or 2 anteriorly directed sharp, blade-shaped spines mounted on bony plates on each side. The caudal fin varies from slightly rounded to highly emarginate. In some species there are long filaments at the tips of the lobes of the caudal fin, sometimes restricted to males. The dorsal fins of these fishes are supported by between 4 and 7 spines and between 24 and 31 soft rays while the anal fin contains 2 spines and 23 to 30 soft rays. There is a single spine and 3 soft rays in the pelvic fins and between 16 and 19 soft rays in the pectoral fins.