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.

[2] It was described by Dmitrii Nikolaevich Taliev in 1955, originally as a subspecies of Asprocottus megalops.

[3] 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.