Common names: sleeper (English), dormilón (Espanol)
Gobiomorus maculatus (Günther, 1859)
Pacific sleeper, Bigscale sleeper
Body elongate, cylindrical, narrowing to rear; head elongate, conical in profile, depressed above; eye a longitudinal oval; mouth large, lower jaw projecting; teeth small conical, in several rows on jaws; teeth on front roof of mouth; gill membranes broadly joined to throat, gill openings extend forward nearly to the level of the angles of the mouth, separated from each other by a very narrow isthmus; dorsal fin VI + I, 9, fins well separated, base of 2nd dorsal < distance from the end of that base to tail fin; anal I, 9-10; second dorsal and anal with angular tips; pectoral 15-16, fin rounded; pelvics I, 5, completely separated; tail fin rounded; scales rough on body, smooth on head, medium (51-57 in lateral series), on body, forehead, cheeks and operculum; no lateral line.
Adult with head and body dark mottled brown; paler below; both dorsal and tail fins clear with rows of small dark spots on membranes; pectoral, pelvic and anal fins clear, pectoral with a dark band at its base. Juvenile with a dark stripe along the midside and 3 bars radiating from the eye (to middle and to rear of mouth, and to the upper corner of the operculum).
Habitat: usually found in freshwater, but enter brackish tidal areas.
Depth: 0-5 m.
The tip of Baja California and the mouth of the Gulf of California to northern Peru, as well as the Galapagos and Cocos.