1, the dogfish belongs to the salmoniform order dogfish family, dogfish genus, mainly distributed in the northern hemisphere frigid to temperate freshwater environment. And blackfish, scientifically known as snakehead, belongs to the order Perciformes, suborder Channa, family Channa, genus Channa, is a common food fish.

2, the two are different in appearance and habits, for example, the dogfish's mouth is flat and large, with a protruding lower jaw, while the blackfish's head is relatively short, with a darker color on the back and top of the head, and a lighter belly.