Lieutenant tang

Geographic Origin and Biotope: Native to the Indian Ocean, ranging from East Africa and Madagascar to Sri Lanka and western Indonesia. Found on seaward reef slopes and shallow channels.

Taxonomy and Morphology: Member of the Acanthuridae family. Oval, compressed body that grows to 31 cm (12 inches). Develops a lunate tail with long filaments as it matures.

Social Behavior: Active open-water swimmer. Displays territorial aggression towards other Acanthurus species as it reaches maturity in home displays.

Coloration and Sexual Dimorphism: Light gray-brown or olive body. Behind the gills, it features two distinctive, parallel black vertical stripes resembling rank bars. No sexual dimorphism.

Aquarium Setup: Demands a very large tank of at least 500 liters (125 gallons) with maximum swimming room. Provide rocky structure at the back of the tank for shelter.

Diet and Feeding: Heavily herbivorous. Feeds on detritus and macroalgae. Provide daily dried nori sheets, spirulina pellets, and vegetable-based flakes. Supplement with frozen foods.

Water Quality: Requires stable parameters and high dissolved oxygen: temperature 24-28°C (75-82°F), pH 8.1-8.4, specific gravity 1.020-1.025, and KH 8-12. Strong current is essential.

Compatibility and Tankmates: Territorial towards other tangs, particularly within the Acanthurus genus. Safe for corals and invertebrates. Best kept as the sole large tang.

Aquarium Reproduction: Unreported in domestic setups. Broadcast spawners with pelagic larval phases that drift in offshore marine currents.

Risks and Diseases: Susceptible to Cryptocaryon irritans (marine ich). Quarantine new arrivals and provide a diverse, vitamin-rich herbivorous diet to prevent HLLE.