The dark sleeper, Odontobutis obscura, is a species of freshwater sleeper native to Japan, and Korea (only Geoje Island). This species can reach up to 25cm (10inches) in length. It is a commercially important species. This species is also variously called Toadonn, Toadfish, and Toadle.
The Dark sleeper diet mainly consists of zoobenthos: chironomids, small aquatic bugs and larvae, which are all found in the benthic zone of the water column.