Surgeonfishes Acanthuridae

Members of the surgeonfish family generally have a compressed body, a single dorasl fin, and a small mouth small with many small teeth.  Many are algal grazers, some feed on plankton. There can be marked colour change from juvenile to adult.  All have spines near the tail. The spines are often surrounded by a warning patch of bright colour. The Family Acanthuridae consist of 3 sub-families:

Surgeons

a single, sometimes venomous, moveable spine on each side of the caudal peduncle, used for fighting and defense.

Acanthurus dussumieri, eyestripe surgeonfish, pencilled surgeonfish Acanthurus lineatus  lined surgeonfish blue-lined surgeonfish, striped surgeonfish Acanthurus olivaceus, orange-spot surgeonfish  orange-blotch surgeon, orangeband surgeonfish
Acanthurus olivaceus, orange-spot surgeonfish  orange-blotch surgeon, orangeband surgeonfish Acanthurus pyroferus, mimic surgeonfish  chocolate surgeonfish Paracanthurus hepatus, blue tang
Acanthurus triostegus, convict surgeon Zebrasoma veliferum, sailfin tang  
Unicorns

several fixed, often curving, defensive spines

Naso unicornis, blue-spine unicornfish Naso unicornis, blue-spine unicornfish Naso vlamingii, Vlaming's unicornfish
>Naso lituratus,orangespine unicornfish    
Sawtails

several bony peduncular plates with a short fixed spine.

Prionurus microlepidotus, sawtail Prionurus microlepidotus, sawtail
Rabbitfishes
family Siganidae
Siganus nebulosus, dusky rabbitfish Siganus nebulosus, dusky rabbitfish Siganus spinus, scribbled rabbitfish
Soles
family Soleidae
Pardachirus hedleyi, southern peacock sole