Big-mouth Sleeper

Photo of the Big-mouth Sleeper, Guavina

Big-mouth Sleeper (Eng.), Guavina del Atlántico (Sp.), Gobiomorus dormitor (Sci.).

Photo courtesy of Eduardo Perusquia. Information compiled by Alan Mowbray, Interpretive Media Writer, EYNF/LEF

General Information

Eliotridae (Sleepers) typically occur in both fresh and brackish waters although some species are truly marine. Eliotridae are found in sub-tropical and tropical regions except the Mediterranean. The Big-mouth Sleeper Gobiomorus dormitor is a common fish from south Florida and south Texas to Brazil.


Gobiomorus dormitor is a dull-colored, light or dark brown to olive, small to medium sized fish. It ranges from 20 to 60 centimeters (7 to 23 inches) in length and can weigh up to 2.030 grams (0.08 ounces). It has a stout body with a short and broad head and blunt snout. It has two dorsal and a broad and rounded caudal fin. Teeth are small and conical in several rows on the jaws.


The Big-mouth Sleeper completes its life cycle in freshwater streams and pools. It is a predator feeding on smaller fish, river shrimp and crustaceans. The Big-mouth lies mostly on the bottom parts of slow-moving streams sometimes on logs, stones, gravel or leaf litter. It relies on its “sluggish” behavior and dull color to capture its prey.


Freshwater streams, rivers and lakes occurring in forests and mountain areas of Puerto Rico.

Where to look for this animal in the EYNF

In quiet pools in the La Mina River (along the La Mina Trail) and pools in the Mameyes River near Puente Roto and at the bottom of the Angelito trail.