Hypophthalmichthys is a genus of large freshwater ray-finned fishes belonging to the family Xenocyprididae, the East Asian minnows or sharpbellies. This genus contains three species. The name comes from Greek ὑπό (hypó 'below'), ὀφθαλμός (ophthalmós 'eye'), and ἰχθῦς (ichthŷs 'fish'), thus 'fish with eyes below', referring to the fact that the fish has its eyes below the mouth line. Members of this genus are native to fresh water in East Asia, ranging from Siberia to Vietnam, but have been widely introduced outside their native range, where often considered invasive. Big head (Hypophthalmichthys nobilis) and silver carps (Hypophthalmichthys molitrix) were initially introduced in the southern Mississippi River basin but have been observed as far north as the Illinois River system outside of Lake Michigan. There are growing concerns of them likely being established in the Great Lakes. The reason is that stakeholders, such as fisheries, recreationists, and the fishing industry can be impacted economically and potentially decrease biodiversity or even extinction of these or other species. Environmental DNA has been used to monitor these species and look for positive eDNA detections and the presence of live organisms. The genus is also known as Bighead carp, though that term is also used for individual species, particularly Hypophthalmichthys nobilis. The Russian language has a special word for the genus - tolstolób(ik) (literally thickforehead).

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