Yellowfin Surgeonfish

Geographic Origin and Biotope: Indo-Pacific: East Africa to the Americas, including Hawaii and the Gulf of California. Found on deep reef slopes and lagoons.

Taxonomy and Morphology: Member of the family Acanthuridae. Largest species in the genus Acanthurus, reaching up to 70 cm. High-backed, compressed body.

Social Behavior: Highly active, constantly swimming. Strongly territorial against other tangs, particularly similarly shaped Acanthurus species.

Coloration and Sexual Dimorphism: Purplish-grey to brown body with bright yellow pectoral fins and yellow margins on the dorsal and anal fins. Genders look identical.

Aquarium Setup: Minimum 1500 liters (not 150!). Requires a massive tank with extensive open swimming channels. Stable rockwork with lots of algae growth is needed.

Diet and Feeding: Omnivore. Needs a high-fiber diet. Provide dried seaweed (nori), spirulina-based pellets, and fresh macroalgae multiple times daily.

Water Quality: Keep temperature at 22-28°C, pH 8.0-8.5, salinity 1.020-1.025 SG. Requires highly oxygenated water with strong, constant water current.

Compatibility and Tankmates: Aggressive towards other surgeonfish. Best kept as the only tang in the tank. Totally reef safe; will not harm corals.

Aquarium Reproduction: Group broadcast spawner. Large spawning aggregations occur in the wild. Larvae are pelagic and have not been reared in captivity.

Risks and Diseases: Highly susceptible to marine ich and skin parasites; UV sterilizer is recommended. caudle spines can cause deep cuts during handling.