Bluespine Unicornfish
Naso unicornis
Bluespine unicornfish is a large coral-reef surgeonfish recognized by the forward horn-like projection on the forehead of adults and the sharp scalpel near the tail. It grazes mainly on algae and commonly moves in loose schools along reef slopes, lagoons, and outer reef drop-offs.
Identification points
- Adults have a distinct horn-like bump projecting from the forehead above the mouth.
- Body is bluish to gray with a long, oval surgeonfish shape and a pointed snout.
- A bright blue spine/knife-like scalpel is present at the base of the tail.
Habitat
Tropical Indo-Pacific coral reefs, reef flats, lagoon reefs, and seaward reef slopes, usually where hard substrate supports algal growth; adults often patrol exposed reef edges and channels.
Bait notes
Not a prime target for bait fishing in most places. Where legal to harvest, small pieces of squid, shrimp, clam, or algae-based baits may take bites; small jigs or soft plastics can provoke strikes when fish are actively feeding, but it is usually more of a spearfishing or incidental catch species.
Behavior
Primarily a daytime grazer that feeds on benthic algae and detritus. Juveniles and adults can school, and larger fish often cruise steadily over reef structure rather than hiding in cover.
Caution
The tail base has a sharp, fixed scalpel that can cut hands badly; handle with care and use a net or gloves. As a reef herbivore, it may be subject to local size or bag limits, and consumption should follow local reef-fish advisories because reef species can occasionally be implicated in ciguatera in some tropical areas.
Fishing notes
Fish near reef edges, surge channels, and reef flats at first light or on moving tide when grazing activity is highest. Use light tackle and avoid heavy pressure around coral; in many regions this species is better observed than targeted, and local rules may restrict harvest in reef areas.