The juvenile largemouth bass eats mostly small bait fish, scuds, small shrimp, and insects. At about a year of age they become cannibalistic, eating other largemouths their size or smaller. As they mature they no longer consume their own kind. Adults consume smaller fish such as gizzard shad, fathead minnows and bluegills. These are swallowed head first. crustaceans such as crayfish are swallowed tail first. Largemouths can consume other fish up to 50% of their own length. sunfish and crustacean they eat tend to be no more than 35% of their own length. They will eat almost anything they can find in the water—snakes, mice, young waterfowl, birds and shrimp.