What do trout eat in streams, rivers, lakes, and oceans?

Trout are primarily predatory fish that consume a varied diet depending on their life stage and environment.12

• General Diet: In their natural habitats, trout feed on insects, small fishes and their eggs, and crustaceans. Newly hatched trout, known as fry, begin their lives by feeding on plankton.1
• Freshwater Environments: In streams, rivers, and lakes, trout are opportunistic predators. When introduced into lakes that contain abundant food fishes but lack other large predators, trout often flourish and grow rapidly by feeding avidly on available prey, including smaller fish species.123
• Marine Environments: Some trout species are anadromous, meaning they migrate to the ocean to feed and mature before returning to freshwater to spawn. In these marine environments, they continue their predatory habits, utilizing the ocean's resources to support their growth.32

Because they are active, swift-moving predators, trout are well-adapted to exploit various food resources across these different ecosystems.24