| Japanese fluvial sculpin, Rhinogobius, Nipponocypris temminckii, Gobioidei, Coreoperca kawamebari|Dark sleeper Wikipedia
The dark sleeper, Odontobutis obscura, is a species of freshwater sleeper native to China, Japan, and Korea. They are known as sleeper perches. This species can reach reach up to 25 cm (9.8 in) in length. This is a commercially important species.