Sea Fish. Is the dragonhead fish a sea fish or a river fish? Dragon head fish is one of the common fish in China and a kind of edible fish. Sea fish and river fish are two kinds of fish with very different habits and living environments. The dragonfish belongs to the latter, is a kind of marine fish, is one of the common marine fish in China. Seawater and river environment... .2. Is the dragonhead fish a deep-sea fish? As mentioned above, the leading fish belongs to a kind of marine fish. However, marine fishes also contain more than one kind and can be further subdivided. Leading fish can be divided into deep-sea fish and shallow-sea fish according to the depth of the sea, and these two kinds of marine fish are distributed in different depths of the sea.