Raccoons, opossums, mink, snakes and muskrats are common land predators for crayfish. Catfish and other ray-finned fish such as bass, pickerel and muskie prey on crayfish. Crayfish also eat each other.
Great blue herons and other aquatic birds eat crayfish. This includes surface feeding birds such as gadfly petrels, frigatebirds, gulls and fulmars. Crayfish escape from their predators by using a tail flip response. This rapid flip of their tails allows them to speed through the water away from danger. Crayfish also use this tail flip to warn each other of danger.
Crayfish are also used as bait for muskellunge, pike, channel catfish, walleye, smallmouth bass, largemouth bass and trout. However, using crayfish as bait is discouraged because they are an invasive species. The rusty crayfish being used for bait eventually take over the habitat of the native crayfish species.
Humans also eat crayfish. People only eat a small portion of their bodies, usually just the tail. Crawfish boils feature crayfish. These are very common in Louisiana.
Though crayfish are not endangered, they do suffer from a disease called crayfish plague. The disease stems from a water mold, and it kills certain species of crayfish. The disease especially affects species found in Europe. Many crayfish are also caught to be kept as pets.