Acanthurus blochii

Ringtail surgeonfish | Blue-banded Pualu | Dark Surgeonfish | Tailring Surgeonfish | Whitetail Lancet | Whitetail Surgeonfish
Acanthurus blochii
Acanthurus blochii, Coral Sea, Australia, Photo: Graham Edgar
Acanthurus blochii
Acanthurus blochii, Coral Sea, Australia, Photo: Ian Shaw
Acanthurus blochii
Acanthurus blochii, Great Barrier Reef, Cairns, Qld, Photo: Andrew Green
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Acanthurus blochii
Acanthurus blochii
Acanthurus blochii


Tropical Indo-Pacific


Similar to A. auranticavus (Ringtail Surgeonfi sh) and A. bariene (Eyespot Surgeonfish), but spot behind eye is yellow. White ring around tail base may be present, but is not a distinguishing feature. Large individuals are often dark and form large schools, and can be very difficult to distinguish from A. auranticavus from a distance. Differs from A. dussumieri by dark, rather than light scute (tail spine).


Max Size: 45 cm

Sea Temperature Range: 23.5-30.7°C

Depth: 2-15m

Habitat Generalization Index: 19.69

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 (18.4% 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: Several (7 per transect)

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

Edit by: Joe Shields