Blackfish is actually snakehead fish, and "snakehead" is one of the nicknames for blackfish.

Blackfish, is the common name of snakehead [lǐ]. Channa belongs to the perch order, Channa family, is the most widely distributed and productive species of fish in the family of Channa, also known as blackfish, raw fish, wealth fish, snakefish, firehead fish, black snakeheads, and so on.