Old wife are a species of perciform fish endemic to the temperate coastal waters of Australia.
It is the only modern species in the family enoplosidae. Old wife are commonly found in pairs or large schools. It has a deep but compressed body with concaved forehead. These features are characteristic of typical butterflyfish. However, the old wife is easily distinguished by its silver and black, vertical, zebra-striped coloration plus its two prominent dorsal fins. Its dorsal fins have bony, knife-like spines – the second dorsal fin is very long and sickle-shaped. These have no obvious venom groove or gland although the spines are widely considered to inflict a painful venom.
The derogatory standard name of this fish apparently refers to the sound made when a fish is caught on hook and line. The teeth are ground together supposedly producing the sound of an ‘old wife’. They grow to about 25cm in length and are found from southern Queensland to Western Australia. Adults are common on coastal reefs and juveniles live in estuaries. The species is carnivorous, eating primarily crustaceans and worms.