Changes colour and grows skin tassels to match seagrass, then hangs head-down in it.
A small filefish to about 12 cm, deep-bodied and laterally compressed, mottled in green, brown and cream with scattered skin flaps and a brush of stiff bristles on the tail base in males. Colour is not fixed: an individual shifts between green and brown over minutes to match the weed it is in, and animals living in seagrass grow longer skin tassels than those on rubble.
Hangs head-down among seagrass blades and weed, holding position with the dorsal and anal fins and moving only when it has to, which is the standard filefish solution to being edible. Feeds on small invertebrates, algae and coral polyps. Recorded from the shallows to about 20 m, and one of the species that makes a seagrass bed worth diving rather than crossing. It is also kept in aquaria to eat Aiptasia anemones, which is why it appears in the trade far from where it is caught.
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.