Hypophthalmichthys is a genus of large cyprinid fish consisting of three species. The name comes from Greek Greek, Ancient (to 1453);: ὑπό ('below'), Greek, Ancient (to 1453);: ὀφθαλμός ('eye'), and Greek, Ancient (to 1453);: ἰχθῦς ('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) have been reaching the Illinois River system outside of Lake Michigan but have grown concerns of them likely being established in the Great Lakes.[1] 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.[2] 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).
The three currently recognized species in the genus are: