Rockfish is a common term for several species of fish, referring to their tendency to hide among rocks.
The name rockfish is used for many kinds of fish used for food. This common name belongs to several groups that are not closely related, and can be arbitrary.
Specific examples of fish termed rockfish include:
The gopher rockfish of the family Sebastidae
The rock greenling of genus Hexagrammos
The Malabar grouper
The western scorpionfish (Scorpaena onaria)