Acanthurus thompsoni

Night Surgeonfish | Thompson's Surgeonfish | Thompson's Tang | Chocolate Surgeonfish | Whitetail Surgeonfish
Acanthurus thompsoni
Acanthurus thompsoni, Maldives, Photo: Rick Stuart-Smith
Acanthurus thompsoni
Acanthurus thompsoni, Niue, Photo: Graham Edgar
Acanthurus thompsoni
Acanthurus thompsoni, Aceh, Indonesia, Photo: Graham Edgar
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Acanthurus thompsoni
Acanthurus thompsoni
Acanthurus thompsoni


Temperate Australasia, Tropical Indo-Pacific


Uniformly dark, oval-shaped body with a lunate, white tail and a rounded head with dark spots. Forms schools which feed on plankton in the water column, well above the reef.


Max Size: 27 cm

Sea Temperature Range: 22.6-31.2°C

Depth: 4-119m

Habitat Generalization Index: 14.78

Also referred to as the SGI (Species Generalisation Index), this describes the habitat niche breadth of the species. Species with values less than 15 are found in a relatively narrow range of reef habitat types (specialists), while those over 25 may be found on most hard substrates within their range (generalists). Learn more here.

Conservation and Rarity

IUCN Status: Least Concern

Occurrence: Frequent (11.8% of sites)

Occurrence describes how often the species is found on surveys within its distribution. It is calculated as the % of reef sites surveyed by RLS divers across all the ecoregions in which the species has been observed

Abundance: Many (13 per transect)

Abundance is calculated as the average number of individuals recorded per RLS transect, where present.

Edit by: Joe Shields