Ctenochaetus truncatus

Squaretail bristletooth | Indian Gold-ring Bristletooth | Yelloweye Bristletooth
Ctenochaetus truncatus
Ctenochaetus truncatus, Seychelles, Photo: Rick Stuart-Smith
Ctenochaetus truncatus
Ctenochaetus truncatus, Aceh, Indonesia, Photo: Ian Shaw
Ctenochaetus truncatus
Ctenochaetus truncatus, Photo: Rick Stuart-Smith
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Ctenochaetus truncatus
Ctenochaetus truncatus
Ctenochaetus truncatus


Temperate Africa, Tropical Indo-Pacific


Grey-brown with small spots over head and body, yellow ring around eye and almost straight rear tail margin. Spots rather than lines on side and straight tail margin distinguish it from C. binotatus (Twospot Surgeonfish), C. striatus (Lined Bristletooth), C. cyanocheilus (Yelloweye Bristletooth), Acanthurus nigrofuscus (Dusky Surgeonfish) and A. nigroris (Greyhead Surgeonfish). In Australian waters, only recorded at Christmas Island.


Max Size: 16 cm

Sea Temperature Range: 25.4-33°C

Depth: 1-21m

Habitat Generalization Index: 5.64

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: Widespread (52.6% 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 (9 per transect)

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

Edit by: Joe Shields