[3] They are especially important as predators in the freshwater stream ecosystems on oceanic islands such as New Zealand and Hawaii that otherwise lack the predatory fish families typical of nearby continents, such as catfish.

[2] Like the true gobies, they are generally small fish that live on the substrate, often amongst vegetation, in burrows, or in crevices within rocks and coral reefs.

Although goby-like in many ways, sleeper gobies lack the pelvic fin sucker and that, together with other morphological differences, is used to distinguish the two families.

[2] Dormitator and Eleotris, two of the most widespread and typical genera, include a variety of species that inhabit marine, estuarine and freshwater habitats.

Among the largest members of the family are predatory species such as the bigmouth sleeper (Gobiomorus dormitor) at up to 90 cm (3.0 ft) from freshwater near the West Atlantic region.