Bait fish

Bait fish are small fish caught for use as bait to attract large predatory fish, particularly game fish. Species used are typically those that are common and breed rapidly, making them easy to catch and in regular supply. Examples of marine bait fish are anchovies, gudgeon, halfbeaks such as ballyhoo, and scad. Some larger fish such as menhaden, flying fish, or ladyfish may be considered bait fish in some circles, depending on the size of the gamefish being pursued. Freshwater bait fish include any fish of the minnow or carp family (Cyprinidae), sucker family (Catostomidae), top minnows or killifish family (Cyprinodontidae), shad family (Clupeidae), sculpin of the order Osteichthyes or sunfish family (Centrarchidae), excluding black basses and crappie.

Bait fish can be contrasted with forage fish. Bait fish is a term used particularly by recreational fishermen, although commercial fisherman also catch fish to bait longlines and traps. Forage fish is a fisheries term, and is used in the context of fisheries. Forage fish are the small fish that are preyed on in the wild by larger predators for food. The predators can be other larger fish, seabirds and marine mammals. Bait fish, by contrast, are fish that are caught by humans to use as bait for other fish. The terms also overlap in the sense that most bait fish are also forage fish, and most forage fish can also be used as bait fish.

...
Wikipedia