What Do Small Fish Eat?
Small freshwater fish typically eat vegetation, insects, larvae, leeches, shrimp and dead or decaying matter, and small saltwater fish, called forage or feed fish, eat plankton. The tiny American herring eats small and larval shrimp as do both Atlantic and Pacific cod.
Feed fish and shrimp are important parts of the aquatic food chain and are a major source of food for predatory fish, sea birds and marine mammals. Shrimp live in oceans, rivers, marshes and streams and are consumed by some of the smallest and the largest of fish as both basking and whale sharks are known to filter them.