The fat sleeper (Dormitator maculatus) is a species of fish belonging to the family Eleotridae, known for their flat heads; they are generally found in fresh water, usually found in lakes, ponds and rivers.

Fat sleepers are small fish whose instance comes naturally bewitnessed with two distinct dorsal fins and seemingly uno scaled, flat head.

Their bodies are a darker brown, whereas their dorsal and anal fins are redder in color.

It lives in intertidal areas on muddy bottoms, and is more frequent in brackish water.

It can be found commonly in freshwater or saline coastal pools and river mouths.