A southern filefish with six spines on each side of the tail base and a variable blue-green pattern. Common on weed and jetty pylons.
To 60 cm, which is large for a leatherjacket. The colour is highly variable. The constant features are a network of fine blue lines on the head and yellow dorsal and anal fins. Males have six strong spines on the base of the tail, which is the name, and in New South Wales a large orange patch on the flank. In females and juveniles the spines are much reduced or absent, so the name only describes half the species.
Other leatherjackets in the same waters are the confusion, and separating females is genuinely difficult. The six tail spines and the fine blue head network are the marks to work from in males.
This is a temperate fish of southern Australia — southern Western Australia east to New South Wales, and Tasmania. It is not a Great Barrier Reef species. Adults are on shelf reef between 1 and 50 m and have been recorded to 100 m; juveniles are in estuaries and shallow bays among seagrass and drifting weed. It eats algae and attached invertebrates and is harmless.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.