Humpback Unicornfish

Geographical Origin and Habitat: Western Indo-Pacific, from East Africa and Seychelles to Samoa and southern Japan. Inhabits current-swept outer reef slopes.

Taxonomy and Morphology: Acanthuridae family, genus Naso. Reaches 60 cm (24 inches). Distinguished by a prominent dark bulbous hump on its forehead and a strongly arched humpback.

Social Behavior: Large pelagic swimmer. Peaceful and gregarious in the wild, forming large schools. Requires vast amounts of open water to swim rapidly.

Coloration and Sexual Dimorphism: Bluish-gray or light olive body with small black dots on the upper back. The frontal bulb and dorsal hump are darker. No obvious sexual dimorphism.

Aquarium Setup: Requires an exceptionally large aquarium of at least 1500 liters. It is vital to leave the central area completely open for fast swimming, placing live rock only along the edges.

Diet and Feeding: Primarily herbivorous, but also consumes zooplankton. Provide fresh marine algae, nori sheets, veggie pellets, and meaty frozen foods like mysis and krill.

Water Quality: Temperature 23°C - 28°C, stable pH 8.1 - 8.4, salinity 1.020-1.025, KH 8-12, GH 15-25. Requires high water flow and heavy filtration.

Compatibility and Cohabitation: Peaceful toward other fish, including surgeonfish of different genera. Can be kept with large or medium-sized reef species. Avoid tiny, timid tankmates.

Aquarium Breeding: Not reproducible in home aquariums due to space constraints. Broadcast spawners releasing pelagic eggs into the open ocean.

Risks and Diseases: Susceptible to Cryptocaryon irritans (ich) and stress from confined spaces. Requires highly oxygenated water and excellent biological filtration.