A larger, mottled jawfish that stays closer to its burrow than the yellowhead. Mouth-brooding males are the reason it is photographed.
To 20 cm. Five or six dark bars along the body and an oblong black spot on the upper half of the dorsal fin. The identification is the upper jaw: it ends in a long thin flexible plate which in males extends back as far as the gill cover and carries conspicuous black bands. That banded jaw is the name. Females have no extension.
The spotfin jawfish is the one to get right. It is closely related, uses the same burrows and overlaps in Florida. It has an eyespot on the dorsal fin — a dark spot with a wide bright white ring — where this species has a plain oblong black spot with no ring, and its males show a single black stripe on a white background inside the jaw where this one has several bands. FishBase lists spotfin jawfish as an alternative name for this species, which is wrong.
It digs and maintains a vertical burrow in sand and rubble near reef, lining it with shell fragments and pebbles that it carries in its mouth and rearranges constantly. It hovers upright above the mouth of the burrow and drops in tail-first when approached. The male incubates the ball of eggs in his mouth, rolling and aerating it. Pairs are monogamous and hold a home range. It lives between the surface and about 44 m and is active by day.
A large male will gape at a diver who crowds the burrow. That is display, not aggression.
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.