Body long and snake-like, without pectoral or ventral fins; dorsal, tail and anal fins form a single, long, continuous fin that begins behind the head, encircles the tail and extends midway down the belly. Body scale-less and coated with a clear, protective mucus layer.
Body heavy, dark brown to black, with irregular, often interconnected, bright yellow chain-like markings. Eyes yellow.
Size: 30 - 45 cm.
Prefer shallow, clear-water reefs and rocky shores, down to 12 meters. Hide during the day in recesses; heads often extend from openings. Forage in open at night, occasionally in tidal zones where they feed on crabs. Constantly open and close mouth in order to move water through their gills for respiration.
Occasional Florida and Bahamas, common Caribbean, south to Brazil.