Acanthurus auranticavus

Ringtail Surgeonfish | Orange-socket Surgeonfish
Acanthurus auranticavus
Acanthurus auranticavus, Raja Ampat, Indonesia, Photo: Rick Stuart-Smith


Tropical Indo-Pacific


Small round black marking behind eye, transparent/light rear tail margin, and dark orange border around dark spine on tail base. Often has white ring around tail base, but this is not a distinguishing feature. Large, very dark individuals can be very difficult to distinguish from A. blochii from a distance, and these species sometimes even school together.


Max Size: 45 cm

Sea Temperature Range: 22.3-31.6°C

Depth: 1-20m

Habitat Generalization Index: 4.18

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: Infrequent (10.0% 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 (8 per transect)

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

Edit by: Joe Shields