About Enoplosus armatus (White, 1790)
Enoplosus armatus, commonly called the old wife (plural old wives), is a species of centrarchiform ray-finned fish that is endemic to the temperate coastal waters of Australia. It is the sole genus and species in the family Enoplosidae. This fish has a deep, compressed body and a concave forehead, features that are characteristic of typical butterflyfishes. Even so, the old wife can be easily distinguished by its silver-and-black vertical zebra-striped coloration, and by its two prominent dorsal fins. The second dorsal fin is very long and sickle-shaped. This species can grow up to 50 centimeters in length. Its dorsal fins bear bony, knife-like spines that do not have any obvious venom groove or gland. Despite this, the spines are widely considered to deliver a painful venom. The common name "old wife" comes from the sound the fish makes when caught, which is produced when it grinds its teeth. Other common names for this species include "bastard dory", "zebra-fish" (a name also used for Girella zebra), and "double scalare". It shares a similar range and appearance with the Moonlighter, Tilodon sexfasciatus.
