Naso lituratus
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Acanthuriformes
Family:	Acanthuridae
Genus:	Naso
Species:	N. lituratus
Binomial name
Naso lituratus (J. R. Forster, 1801)
Synonyms[2]
Acanthurus lituratus Forster, 1801 Callicanthus lituratus (Forster, 1801) Aspisurus carolinarum Quoy & Gaimard, 1825 Prionurus eoume Lesson, 1831 Monoceros garretti Seale, 1901

Naso lituratus, the clown unicornfish, orangespined unicornfish, black-finned unicornfish, Pacific orangespined unicornfish, blackfinned unicornfish or stripefaced unicornfish, is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs. This fish is found in the eastern Indian Ocean and western Pacific Ocean.

Unique to members of Acanthuridae, including Naso lituratus, are the Epulopiscium bacteria. These bacteria influence the digestion of Naso lituratus, helping them process the algae in their diet.^[3][4][5]

Naso lituratus can be found in the Indian Ocean and the Pacific Ocean. This species can be easily recognised by two bright orange forward-hooked spines on the caudal peduncle (the tail base), its orange lips and black face mask. The body is brownish grey with yellow nape and there is a broad black band on the dorsal fin. It reaches about 45 cm (18 in) in length.^[6]

It can be found on coral reefs, often in pairs.

Naso lituratus was first formally described in 1801 as Acanthurus lituratus by the German naturalist Johann Reinhold Forster without stating a type locality, although this is considered to be Tahiti in the Society Islands of French Polynesia.^[7] This species is classified within the nominate subgenus of the genus Naso.^[8] The genus Naso is the only genus in the subfamily Nasinae in the family Acanthuridae.^[9]

The features of Naso lituratus include orange lips, a caudal peduncle with a brash-hooked spine, and a black face mask. The descriptions of these features include one dorsal fin on top of head and is encircled by a broad black band around 45 centimeters long. They barely grow in size. Long anal fin with II spines and 28–30 soft rays, and a continuous, unnotched dorsal fin with VI spines and 27–30 soft rays. Contains 8 to 9 gill rakers on the lower leg whereas the upper limb has 4. There are 6 spines in total, each with 26–29 soft rays. Adipose fins do not exist. There is one anal fin, two spines overall, and between 27 and 30 soft rays on it. The pectoral and pelvic fins are two of its paired fins. The pectoral fin contains 17–18 soft rays and 0 spines. The pelvic fin has a single spine and three soft rays. In adult males, the lobe's apex produces a lengthy filament. Caudal fin is lunate or crescent-shaped. Two sharp blades that point forward are on the caudal peduncle. In Juveniles, their blades are not fully grown, as they have a stifling gray-brown tint with black, yellow, and white patterns. No forehead "horns" or front protuberance that can be seen in certain other Acanthuridae species.^[10]

Naso lituratus live in the East Indian and Pacific Ocean, with their habitat is living in the coral reefs that lay around in those specified oceans. The reproduction of this species are that the sexes are separate among the Acanthuridae and have distinct differences in size. Spawning occurs year round in Guam. They need high oxygen levels, strong water currents, same companions and need to feed on wild algae. Their self defense tactic is that they will extend their strong tail spines to strike any approaching predators.^{[citation needed]}

Naso lituratus has various human use including as a food source and as a commodity in the pet and aquarium trade.^{[citation needed]}

• Photos of Naso lituratus on Sealife Collection