A small transparent goby that hovers in clouds of hundreds inside caves and under ledges, lit orange by a torch.
To 4 cm. Translucent orangish-grey above shading to violet-grey below, with two orange lines running back from each eye and a line of orange and white blotches along the spine from eye to tail. The dorsal fin rays carry red. There is a low fleshy crest along the midline of the head and a transparent patch on top of the head, a dark streak under the tail base, and a black ring around the anus.
The glass goby is the classic Caribbean pair that cannot reliably be separated underwater, and it is better to say so than to pretend. Both have the black anal ring, so that is not the check. The glass goby has a dark stripe running forward from the eye across the snout, about eight elongate white dashes along the spine and orange on the sides of the head; this species has no dark marking forward of the eye and has the fleshy head crest and the transparent patch on top of the head. Behaviour helps a little: the glass goby hovers about half a metre off the bottom at drop-offs and ledges, this one in caves and shade.
It gathers in schools hovering above the bottom in caves, under overhangs and in shaded parts of the reef between about 2 and 70 m, feeding on plankton. It changes sex as it grows.
It is listed as vulnerable, which is unusual for a small common goby, on the basis of projected loss of coral habitat rather than any direct pressure on the fish.
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.
