Description:

Dorsal spines: 9; Dorsal rays: 25-27; Anal spines: 3; Anal rays: 24-25.

Blue grey body with, in life, numerous very small brownish yellow spots that tend to form irregular longitudinal lines. Head with irregular yellow-brown stripes and an 
irregular orange-yellow spot behind the eye. Opercular membrane black. Dorsal fin yellow with narrow blue bands. A narrow blue margin on the dorsal, anal caudal fins. 
A blue to black margin around caudal spine socket. Base of caudal fin usually encircled by a white bar. Vertical stripes apparent in the central area of the caudal fin. 
Underwater this fish may appear black with a lighter bar across the caudal peduncle.

Maturity: Lm unknown. Range unknown. Max Length: 45cm TL.

Adults in outer lagoons and seaward reefs (depth 2-15m), usually in small groups. Juveniles settle in coral rubble. Grazer/detrivore feeds on the algal film covering 
compacted sand, diatoms and detritus

This species is not protected or subject to fishery regulations. It is caught in the fish trap fishery, it is unclear how abundant it is in the catch because a cursory 
glance of dead specimens can readily be mistaken for A. xanthopterus, A. dussumieri or A. mata.

A. blochii is often confused with A. xanthopterus with which it shares its Creole name. The latter differs in having the outer third of the pectoral fin yellow and the 
dorsal fin with 4 blue bands as opposed to 8 in A. blochii. A. blochii differs from A. dussumieri in having vertical stripes rather than spots on the blue central area 
of the caudal fin. It differs from A. mata in having a lunate caudal fin.

Bray, D.J. (2017). Acanthurus blochii in Fishes of Australia, http://fishesofaustralia.net.au/home/species/1022 (06/11/18).

Choat, J.H. et al. (2012). Acanthurus blochii. The IUCN Red List of Threatened Species 2012: e.T177971A1507181. http://dx.doi.org/10.2305/IUCN.UK.2012.RLTS.T177971A1507181.en. (06/11/18).

Froese, R. & D. Pauly. Eds. (2018). FishBase. https://www.fishbase.de/summary/acanthurus-dussumieri (06/11/18).

McGrouther, M. (2013). Dark Surgeon, Acanthurus blochii. https://australianmuseum.net.au/dark-surgeon-acanthurus-blochii-valenciennes-1835 (06/11/18).

Randall, J.E. (2001). Surgeonfishes of Hawaii and the World. ISBN: 1-56647-561-9

Nevill, J.E.G. & Mason-Parker, C. (2019). Acanthurus blochii, Ringtail surgeonfish. www.seatizens.sc. https://seatizens.sc/species/acanthurus-blochii-valenciennes-1835-2/ (Edited 11/06/22).