Sailfin Tang

The sailfin tang is the largest species of the genus Zebrasoma. Its dorsal and anal fins are so tall that when fully raised the fish looks almost as tall as it is long; it usually does this when it sees a rival or its own reflection. Its body is covered with dark brown and pale yellowish vertical bands, which in turn are crossed by thin yellow lines. Juveniles have brighter yellow–black bands.

It is often confused with its Indian Ocean twin, the Desjardini tang (Z. desjardinii); the Desjardini has small pale spots on the head and belly, whereas in the sailfin tang lines dominate instead of these spots. Its old scientific name is Zebrasoma veliferum, and it is still sold under this name in the trade. All specimens are wild-collected.

It lives in lagoons and outer reefs of the Pacific. Juveniles shelter alone among rocks or corals in shallow and sometimes turbid water; adults graze on algae in more open areas. In the wild it feeds on leafy macroalgae.

• Volume: At least 1000 liters and 200 cm in length for an adult. A 10 cm juvenile can start in a smaller tank, but it grows quickly; the adult aquarium should be planned from the start.
• Water: Salinity specific gravity 1.023–1.026, pH 8.1–8.4, temperature 24–27°C. Plenty of oxygen and strong flow.
• Decor: Wide open water where it can spread its fins; shelter crevices along the sides.
• Reef compatibility: Reef-safe; it leaves corals and invertebrates alone. It may eat macroalgae in the aquarium (e.g. Caulerpa).

Herbivorous. Offer dried seaweed (nori), spirulina and granules containing seaweed every day; frozen mysis and brine shrimp can be added occasionally. It eats eagerly and greedily, but if green food is lacking its color fades and head and lateral line erosion can appear.

Relatively calm compared with other large tangs. It responds to its own kind and similarly shaped tangs by spreading its fins and threatening with its scalpel. It causes no trouble with differently shaped fish.

Good companions: In a large aquarium, clownfish, anthias groups, wrasses, dwarf and Genicanthus angelfish, a tang from a different genus (e.g. Naso or Acanthurus).

Avoid: A second Zebrasoma, narrow and short aquariums, fin-nipping triggerfish.

Kept as a single specimen in the aquarium. If more than one tang is planned, they should be chosen from different genera and added at the same time, or starting with the most docile species.

In the wild, pairs release pelagic eggs into the water column, usually in the morning and afternoon, often with the outgoing tide. It does not breed in the home aquarium.

• Marine white spot and velvet: Quarantine and good nutrition are the best protection.
• Head and lateral line erosion (HLLE): Seen with insufficient green food and poor water quality.
• Fin damage: Its tall fins can tear in a narrow aquarium.

Cannot be reliably distinguished externally.