Plain grey snake eel with a black-edged dorsal fin and no markings on the face.
A snake eel reaching about a metre, plain grey to olive or brown over the whole body with no bars, spots or facial pattern, and a dorsal fin narrowly edged in black — the mark the name refers to, and the one visible feature when the animal is out of the sand. The head is unremarkable and the eyes sit well back from the snout tip, which places it in Ophichthus rather than Brachysomophis. Against the Napoleon snake eel Ophichthus bonaparti the separation is straightforward: that species has a yellowish face heavily marked with dark blotches and a banded body, where this one has neither. Juveniles are darker and can look almost black.
Buries in soft sediment with the head clear and the body in a tunnel below, and feeds at night on small fish and crustaceans taken near the burrow mouth. It burrows backwards using the hard, finless tail tip. Because the head carries no pattern it is easy to pass over on a night dive, and it is likely under-recorded relative to the more strikingly marked snake eels on the same ground.
Recorded from about 2 to 25 m on silty sand and rubble, including the fine sediment close to river mouths and inshore slopes. The usual caution applies to any buried eel: the sand within a metre of the head is left alone, and the animal is approached low and from a distance rather than from directly above.
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.
