Spinycheek Sleeper

Photo of the Spinycheek Sleeper/Morón

Spinycheek Sleeper, Small-scaled Spinycheek Sleeper (Eng.), Morón (Sp., Puerto Rico), Eleotris pisonis (Sci.), native, freshwater streams, Southeastern US (continental shelf), Gulf of Mexico (continental shelf), Bahaman Islands, Brazil, Greater Antilles, Lesser Antilles islands.

Photo Marcelo Vianna, 02/05/01. Information compiled by Alan Mowbray, Interpretive Media Writer, EYNF/LEF

General Information

Class-Actinopterygii (spiny-rayed fishes), Order-Perciformes (perch-like fishes), Family-Eleotridae (sleepers), Genus-Eleotris, Species-pisonis. Although native to Puerto Rico, until quite recently, this species had not been recorded in the streams and rivers of the El Yunque National Forest.


The Spinycheek Sleeper can be recognized by its light brown head and dorsum, darker brown flanks and whitish-gray dorsal spines, dorsal and anal soft rays and brownish tail fin. Average size of a mature E. pisonis male is 9.8 inches (25 centimeters). Although anatomically similar to the goby, E.pisonis lacks the goby’s characteristic “pelvic fin sucker” which distinguishes Eleotridae from most Gobiidae species.


Adult Spinycheek Sleepers feed mostly on dipteran (flies, mosquitoes, gnats) larvae and crustaceans such as crabs and shrimps and even small fishes. Their diet may vary slightly as they mature sexually.


Although Spinycheek Sleepers spend their planktonic stage in brackish, estuaries (where freshwater streams meet the sea), adults of the species are occupy fresh water streams, on shallow, muddy or sandy bottoms.

Where to look for this animal in the EYNF

This species is rarely recorded in El Yunque’s streams; shallow pools along the Rio La Mina, below the Palo Colorado Interpretive Site may offer visitor’s a possible viewing opportunity.