All fish / Acanthuridae

Thompson's surgeonfish

Acanthurus thompsoni

Also known as thompson's tang, thompson surgeonfish, chocolate surgeonfish, night surgeonfish, thompsons tang, white-tail tang, ニジハギ, 汤氏刺尾鱼

This is a slim, deep-bodied tang that varies from plain grey-brown to bluish, often with a pale or white tail and a dark spot where the pectoral fin meets the body. Unlike most surgeonfish, it feeds mostly on zooplankton in open water. That makes it fairly reef-safe and less aggressive than many other tangs, so it suits reef keepers who want an active mid-water fish.

Care at a glance

Care level

Moderate

Temperament

Semi

Adult size

20 cm

Temperature

24 to 28 °C

pH

8.1 to 8.4

Smallest tank

500 litres

Keep as

Keep one, or a small group added at the same time in a very large tank

Diet

Omnivore: mysis, krill, enriched brine shrimp, copepods, quality marine flakes and pellets, with some nori

Swims

Middle of the tank

Lifespan

5 to 10 years

Water

Marine (saltwater)

Wild range

Indo-Pacific, from East Africa to Hawaii and the Pitcairn Islands

Breeding

In the wild it spawns in open water and its eggs and larvae drift in the plankton. It has not been bred in home aquariums in any reliable way, so nearly all fish sold are wild caught.

Good to know

Like all surgeonfish it has a sharp spine either side of the tail base, and it can pick up marine ich (white spot), so quarantine new fish. It needs several feeds a day and plenty of open swimming room. Do not confuse it with the more aggressive grey or brown Ctenochaetus tangs.