Rhinogobius is a genus of small freshwater gobies in the family Gobiidae, widespread across East Asia: China, Japan, South Korea, Taiwan, Vietnam, Laos, Hong Kong, and the Russian Far East, per the atlas's coverage. They are bottom-dwelling stream fish with the fused pelvic-fin sucker typical of gobies, used to hold position on rock in current, and breeding males develop striking dorsal-fin extensions and color patterns used in territorial and courtship display. The atlas covers 25 species, from about 1–5.5 in, and the genus remains taxonomically active, with regional color-pattern populations still being sorted into formally described species.
Rhinogobius has a devoted following among biotope and native-fish keepers, particularly in Japan and Taiwan, where species such as the river goby (R. flumineus) and the ancient-lake endemic Lake Biwa goby (R. biwaensis) are kept in cool, current-swept, rock-floored tanks that mimic their home streams; males guard eggs laid on the underside of a stone until they hatch. Formal conservation assessment lags well behind the genus's real diversity, with the large majority of species not yet evaluated, so while a few, like the Amur goby (R. brunneus), are considered secure, the true status of most Rhinogobius remains unknown.