Hypseleotris, the carp gudgeons, are small gobioid fish, family Eleotridae, found across a broad swath of the Indo-Pacific, from Australia and New Guinea through Indonesia, Micronesia, and Fiji to outlying populations reported from India, Japan, and Madagascar. Most species inhabit slow-flowing rivers, billabongs, and estuarine reaches, tolerating a range of salinity, and stay small — roughly 1.5–4.5 in — with a stocky, rounded body typical of gudgeons rather than the elongated shape of true gobies. Several Australian species were long lumped together as look-alike complexes before genetic work helped resolve them into distinct taxa.
Carp gudgeons are chiefly of interest to native-fish keepers, particularly in Australia, rather than the mainstream aquarium trade; species such as the empire gudgeon (H. compressa), firetail gudgeon (H. galii), and western carp gudgeon (H. klunzingeri) show up in dedicated native-species tanks and ponds for their hardiness and locality-specific colouration rather than flashy pattern. Care is generally undemanding — unfussy omnivores tolerant of a range of temperatures — which suits their role as an entry point into native fishkeeping. Conservation status varies by species; most of the atlas's eleven are secure or unassessed, but two are Near Threatened and one Endangered, reflecting pressure on wetland and floodplain habitat across parts of the genus's range.