The barfin flounder (Verasper moseri) is a flatfish of the family Pleuronectidae. It is a demersal fish that lives on sandy, muddy bottoms at depths of up to . It can reach up to in length and can weigh as much as . Its native habitat is the northwestern Pacific, specifically the Sea of Okhotsk, Japan's northern Pacific coast, the Strait of Tartary and the Kuril Islands.