Dormitator is a genus of sleeper gobies in family Eleotridae, close relatives of the true gobies (Gobiidae) but lacking the fused pelvic-fin sucker that lets gobies cling to surfaces. The atlas covers 3 species - the Pacific fat sleeper (D. latifrons), the African fat sleeper (D. lebretonis) and the Atlantic fat sleeper (D. maculatus) - spread across Mexico, Central America, the Caribbean and the southern United States on one side of the Atlantic, and West Africa (Benin) on the other. All three live in brackish estuaries, mangrove creeks and coastal lagoons, burrowing into soft mud and tolerating the low-oxygen, fluctuating-salinity conditions typical of these habitats.
Fat sleepers are thickset, heavy-bodied fish that can grow large for a goby relative - sizes recorded in the atlas span roughly 3–27.5 in - and across their range they are a genuinely important artisanal food fish rather than a mainstream aquarium staple. A handful of brackish-water and biotope specialists keep them as bold, hardy oddball fish, but their size and predatory habits make them a species-tank proposition rather than a community fish. Conservation data are limited: two species are assessed Least Concern and one has not yet been evaluated, in keeping with how little formal survey work reaches estuarine gobies generally.