Cyphocottus eurystomus is a species of ray-finned fish belonging to the family Cottidae, the typical sculpins. These sculpins are endemic to Lake Baikal in Russia. It was described by Dmitrii Nikolaevich Taliev in 1955, originally as a subspecies of Asprocottus megalops.[1] It is a freshwater fish which is endemic to Lake Baikal, Russia. It is known to dwell at a depth range of 50–600 metres.