Size27.6 inches (70 cm)
DietCoarse and leafy brown algae
HabitatChannels, moats, lagoons and seaward reefs
- Body usually greenish-gray in color with a bony horn or rostrum protruding from the front of its head in front of the eyes.
- Dorsal and anal fins are yellowish with thin blue lines.
- Two blue plates with sharp, forward-pointing spines on either side of the caudal peduncle.
- Thick leathery skin with tiny non-overlapping scales and small teeth with finely serrated edges.
- Lobes of the caudal fin are extended into slender thread-like filaments; more apparent in the male.
- Can reach approximately 27.6 inches (70 cm) in length.
Unicornfish are named for the bony horn on its face.
- Diet consists of coarse and leafy brown algae.
- Occurs in the Indo-Pacific from the Red Sea and East Africa to the Marquesas and across the tropical Pacific to southern Japan, throughout Micronesia and east to Hawaii.
- Juvenile lives on clear coastal reefs with algae growth.
- Adult prefers shallow reef slopes adjacent to deep water.
- Found in channels, moats, lagoons and seaward reefs, particularly in areas with strong surges, preferring depths usually no greater than about 33 feet (10 m).
- Has been observed practicing pair spawning, particularly at the outermost area of a foraging group.
- In some areas, it has been observed migrating in schools around the outer reef edges and spawning during both the full and new moons.
- “Not Evaluated” on the IUCN Red List.
- Does not recover quickly from environmental or other stresses since its population doubles between 4.5 and 14 years.
- With age, the male tends to have a better-developed horn, peduncular spines (spines in plates just before the tail), and caudal (tail) filaments than its female counterpart.
- Usually swims within a small group.
- Function of the rostral horn on the forehead is unknown.