A blenny drawn out to half a metre, living head-up in a hole in the sand. Also called the hairtail blenny.
An extremely elongate blenny reaching about 55 cm, also called the hairtail blenny, pale yellow to grey with a row of dark blotches or bars along the flank and a long low dorsal fin running most of the body. The proportions are unlike anything else in the family: the body is ribbon-thin and eel-like, the head small, and the jaws carry a pair of long curved canines. Divers who meet one for the first time usually log it as a small eel, and the character that settles it is the blenny’s high-set, mobile eyes and the single continuous dorsal fin.
It lives in a hole in soft sediment and spends most of its time in it, with the head and the first part of the body held straight up out of the opening, swaying slightly. Disturbed, it withdraws in one movement and does not come back quickly. Away from the burrow it swims with a slow sinuous roll, and animals are sometimes seen well clear of the bottom at dusk. Recorded across the Indo-West Pacific on silt and fine sand from a few metres down.
Most of what is published on the species comes from trawl and market material rather than from observation in the water, so the diet, the breeding and the reason for the evening swimming are not well described. Sightings are irregular enough that the fish is usually found by a guide who knows a particular stretch of silt rather than by searching.
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.