A large dark eeltail catfish with white lips and a pale line along the fin margins.
An eel-tailed catfish reaching about a metre, dark grey-brown to nearly black, with conspicuously white lips, four pairs of barbels around the mouth and a narrow pale margin along the fin that runs continuously around the tail. Young fish are paler and often carry a faint stripe that fades with growth. The striped catfish Plotosus lineatus, which has its own entry, is much smaller, keeps two clean cream stripes for life and forms dense balls as a juvenile.
Adults are solitary or in twos and threes, working over silty sand near pilings, wrecks, seagrass and mangrove edges, and are seen at any hour rather than only at night. Feeding is by dragging the barbels through soft sediment and taking worms, crustaceans and small fish by suction, which leaves shallow furrows and a trail of raised silt behind the fish.
Recorded from the eastern Indian Ocean through Indonesia to New Guinea and northern Australia, from the shallows to about 30 m, and it tolerates brackish water at river mouths. The size and the slow, deliberate movement make it one of the easier large fish to photograph on a muck site, though the black body against black sand needs the light close in on one side.
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.