Worm-thin, with an orange stripe from eye to tail, hovering just clear of the sand.
A wormfish to about 12 cm and no thicker than a pencil lead, the body pale bluish white with a bright orange to orange-red stripe running from behind the eye to the tail, and blue lines and edging on the head. The dorsal and anal fins are long and low and run almost the length of the body, and there is no separate spiny dorsal of the kind a dartfish carries. Two congeners overlap with it: Gunnellichthys viridescens is greenish-yellow without the orange stripe, and Gunnellichthys monostigma is plain pale with a single dark spot on the gill cover. At distance a wormfish is most often mistaken for a small dartfish (Ptereleotris), but the wormfish is far more elongate, swims with a continuous eel-like undulation and stays within a few centimetres of the bottom.
Hovers just clear of open sand and fine rubble, singly or in pairs, picking small planktonic animals from the water immediately above the sediment. When alarmed it drops into a hole in the sand or under a piece of rubble, entering tail-first, and it can be some minutes before it reappears. Recorded from about 12 to 40 m and generally commoner on the deeper part of a slope than the shallow end. The fish does not hold position under pressure so much as retreat steadily ahead of a diver, keeping a fixed distance, so it is easier to work by settling on the sand well short of it and letting it come back along its own line.
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.
