The Palefin Unicornfish (Naso brevirostris) is also known as the Shortnose Unicornfish, and the Spotted Unicornfish. They are the most common Unicornfish in Tanzania.
Fishes within the Acanthuridae family have blades on their tails. The Acanthurus genus are known as Surgeonfish and those that fall within the Naso Genus are known as Unicornfish. Although both have blades in the caudal area, Unicornfish have two blades. The blades pictured below are used for defense and possibly in territorial disputes and can inflict significant damage. The blades are reported to contain toxins but there seems no scientific evidence for this.
The Palefin Unicornfish has an oval shaped body that is laterally compressed. The mouth is forward on the body and the eye is set quite far back on the body thereby protecting the eyes while feeding. Adults have a prominent horn.
The colors are highly variable and they are capable of changing colors dependent on mood. The normal base color is a light brown colour with irregular markings on the rear of the body. The markings fade out in the area behind the gills and return forward of the gills over the facial area.
The fish is capable of putting a blue patch in the area behind the gills as seen in the header image. They are also capable of turning the whole body a light blue color. The rear of the caudal fin is white. They grow up to 60 cm in length but around 50 cm is more common in the wild.
PALEFIN UNICORNFISH IN THE WILD
The Palefin unicornfish is common in Tanzanian coastal waters and is often seen in large shoals. They are most commonly seen in the 12 to 20 meter range but do go deeper and have been recorded at 122 meters. They are active fish always on the move.
Palefin unicornfish are found across the Indo Pacific area. They adults are most common close to deep drop offs. The juveniles are usually in shallower waters from 10 to 18 meters and hide on the reef. At night the adults are often seen individually or in pairs hiding in small caves.
The juvenile Palefin unicornfish are grazers and feed on benthic algae whereas the adults feed on plankton.
Group spawning takes place with the females releasing spawn into the water table and the dominant male fertilizing the eggs. Once the eggs hatch the larvae go through a planktonic stage.
Palefin Unicornfish are not commonly kept in aquariums presumably mainly because of their size but are sometimes seen in public aquariums.
PALEFIN UNICORNFISH CLASSIFICATION
Species: N. brevirostris
- The Reef Guide: Southern Africa’s East and South Coasts