TAXONOMY
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii (ray-finned fishes)
Order: Perciformes (Perch-likes)
Family: Acanthuridae (Surgeonfishes, tangs, unicornfishes)
Genus/species: Acanthurus achilles
GENERAL CHARACTERISTICS: The Achilles Surgeonfish’s black body is ovate and compressed with a large orange caudal spot. The caudal fin has a broad vertical orange band. The spine in caudal peduncle may be venomous. Juveniles lack the orange spot.
Length to 24 cm (9.5 in)
DISTRIBUTION/HABITAT: Central Pacific: Micronesia, New Caledonia, Hawaii to Pitcairn and east to of French Polynesia Island. Found on clear seaward reefs, primarily in the surf zone to 4 m (12 ft). Usually in small groups.
DIET IN THE WILD: Diurnal herbivores of filamentous and small fleshy algae.
REPRODUCTION: Monogamous spawners
MORTALITY: An important food fish on tropical islands.
REMARKS: “Tang” in British dialect means dagger or knife. Thus the common name refers to the caudal peduncle spines. Single scalpel-like peduncular spine folds into a groove on each side of the tail. Spines are used offensively or defensively, against conspecifics in struggles for dominance or against predators. Whether a fish has a common name of “surgeonfish” or “tang” seems to be a matter of convention, not substance. The generic name comes from the Greek acantha (“thorn”) and oura (“tail”).
References
California Academy of Sciences Steinhart Aquarium Philippine Coral Reef 2016
fishbase www.fishbase.org/summary/Acanthurus-achilles.html
IUCN Red List www.iucnredlist.org/details/177960/0
EOL eol.org/pages/210872/details
Ron’s flickr http://www.flickr.com/photos/cas_docents/4330628500/in/set-72157625992053826/
Ron’s WordPress shortlink http://wp.me/p1DZ4b-1ah