Description
Acanthurus olivaceus, commonly known as the Orange Shoulder Tang, is a large and visually distinctive surgeonfish known for its dramatic color transformation as it matures. Juveniles display a bright yellow body, while adults develop a more subdued grey to olive coloration with a striking orange patch on the shoulder, creating a bold contrast and a unique visual progression within reef aquariums. Its size, presence, and constant grazing behavior make it a strong feature fish in larger systems.
Native to the Indo-Pacific, the Orange Shoulder Tang thrives in spacious aquariums with abundant rockwork and open swimming areas.
Lighting: Moderate to high; adapts well to standard reef lighting
Flow: Moderate to high; prefers strong, well-oxygenated water movement
Placement: Active swimmer occupying mid to upper levels with access to open space
Temperature: 75–80°F (24–27°C)
Salinity: 1.0265 SG (35 PPT)
pH: 8.1–8.4
Alkalinity: 8–10 dKH
Diet: Herbivorous; requires a diet rich in marine algae, nori, and high-quality herbivore preparations, supplemented with frozen foods
Aggression: Semi-aggressive; may show territorial behavior toward other tangs, especially similar species
Adult Size: Up to 35 cm
Care Level: Intermediate – hardy but requires ample space and stable water conditions
Compatibility: Reef-safe; generally compatible with most reef inhabitants but best housed in larger aquariums with careful stocking of other tang species
