Insects

• Different aquatic environments support different species of insects. The most common for trout are mayflies, caddisflies, stoneflies, midges and terrestrial insects such as grasshoppers and ants. Stoneflies and caddisflies are generally found in fast, well-oxygenated water, while midges and mayflies are found in both still and moving water. Terrestrial insects are usually ingested on windy days when they are blown into the water.
  
  

Baitfish

• Baitfish is a generalized term for any small fish. Baitfish commonly found in rainbow trout waters include dace, minnows and sculpins. Rainbow trout and other game fish will chase a single baitfish or focus on schools of baitfish. To make hunting easier and to conserve energy, a wounded baitfish is the most likely target. Crayfish are another important food source that are sometimes categorized as baitfish. The crayfish, or crawdad, is vulnerable when it molts its hard exterior shell.
  
  

Mammals

• Mammals are a major food source for large rainbow trout and other game fish. In Alaska and on the Russian Kamchatka Peninsula, it is common for rainbow trout to feed on mice and lemmings. Birds also provide a food source when they nest in trees that overhang a lake or river. Small birds can fall out of the nest and into the water, where they are vulnerable and have difficulty taking flight.