Catfish have a wide variety of predators, including snakes, raccoons, mink, otters, wading birds, alligators, crocodiles, large lizards, humans and other fish. As with most species, catfish have more predators when they are young than when they reach maturity. Some old, large catfish may effectively outgrow all of their predators except humans.
Predatory fish, such as largemouth bass, smallmouth bass, perch, walleye, striped bass and pike, frequently eat young catfish. Additionally, larger catfish are one of the most important predators of young catfish. Terrestrial animals most often hunt catfish in shallow water. Alligators and cottonmouths frequently gather at drying water holes to consume the catfish that have become stranded. Brown water snakes, a nonvenomous species from the southern United States, primarily subsist on catfish. These snakes will grasp branches with their tails while dunking their heads underwater until they can secure a small catfish. Many other water snakes consume catfish as the opportunity presents itself.
Because they are eaten by so many predators, many catfish have evolved barbs or other features to protect themselves. Many have spines that deliver venom into any would-be predator. Some catfish have even developed the ability to deliver a strong electric shock to any animals that touch them.