Clown Tang

Clown Tang

The Clown Tang (Acanthurus lineatus), or lined surgeonfish, is one of the most spectacular fish on the reef — its body blazing with electric blue and orange-yellow horizontal stripes. But its beauty is matched by a notoriously fierce temperament and demanding care needs. Highly aggressive, fast-growing and prone to disease, it is firmly an expert-only fish that requires a very large tank and careful management.

It is a stunning centrepiece for those equipped to keep it, but a poor choice for most aquariums.

Natural Habitat & Origin

Acanthurus lineatus is widespread across the Indo-Pacific, where it lives on shallow, high-energy reef crests and surge zones with strong wave action and abundant algae. It is fiercely territorial in the wild, defending prime grazing patches against other herbivores.

In the aquarium it needs to mirror that environment: powerful flow, excellent oxygenation, open swimming space and abundant algae for grazing.

Care Requirements

Maintain stable marine conditions: salinity around 1.024–1.026, pH 8.1–8.4, and a temperature of about 24–26°C (75–79°F), with very strong flow and high oxygen levels. It is a large, extremely active fish — reaching up to about 38 cm (15 inches) — and needs a very large tank, on the order of 700 litres (around 185 US gallons) or more, with plenty of length to swim. It is sensitive to poor water quality and stress.

Diet & Feeding

The Clown Tang is a herbivore that grazes algae voraciously in the wild. Offer a generous, primarily plant-based diet: dried marine algae (nori) on a clip, herbivore and spirulina preparations, and algae-based frozen foods, fed frequently throughout the day. Abundant natural algae growth is a major asset; a poorly fed Clown Tang declines quickly.

Behavior & Temperament

This is one of the most aggressive surgeonfish in the hobby — territorial and combative toward other tangs and often toward unrelated fish too. It should be the only tang in the system and is best added last, to robust tankmates, in a tank large enough to dissipate its aggression. Its sharp caudal spines are formidable weapons; handle with great care.

Tank Mates

House it only with large, robust fish able to withstand its temperament — big wrasses, large angelfish, and similarly assertive species — in a very large tank. Avoid other tangs and any timid fish. It is reef-safe, grazing algae rather than corals or invertebrates, but its aggression and size limit its suitability to large, fish-robust reefs.

Breeding

Acanthurus lineatus is a pelagic spawner with planktonic larvae and is not bred in the home aquarium. Trade specimens are wild-collected.

Common Health Issues

The Clown Tang is notoriously susceptible to marine ich (Cryptocaryon irritans) and marine velvet (Amyloodinium ocellatum), and it ships and acclimates poorly, making a careful quarantine essential. It is also intolerant of low oxygen and poor water quality. Provide pristine, well-oxygenated water with very strong flow, a large tank, an algae-rich diet and a low-stress introduction — and only attempt this magnificent but difficult fish if you can meet all of those demands.