Order: Cottiformes, Family: Agonidae
The body of Atsumori-Uo is covered with a bright red hard shell like armor. The name is due to this red body color which reminds one of Taira-no Atsumori, the young Heike samurai who was wearing red armor in the battles of the Genpei War.
The Atsumori-Uo has a single protrusion, a barb, on the edge of its top jaw and the first dorsal fins are large and shaped like a triangle when open.
The fish lives in the northern part of the Pacific Ocean and the Sea of Japan, as well as in the Sea of Okhotsk.