Gadus is a genus of demersal fish in the family Gadidae, commonly known as cod, although there are additional cod species in other genera.The best known member of the genus is the Atlantic cod.Until recently, three species in the genus were recognized. Modern taxonomy also includes a fourth one, the Alaska pollock (Gadus (=Theragra) chalcogrammus), which is not separate from the Norway pollock. Furthermore, Greenland cod (G.