The rainbow trout is a popular sport fish. Like many other trout, there are resident freshwater and sea-run subspecies. They will follow salmon up to their spawning grounds to feast upon loose or damaged eggs.
Although the rainbow trout is native only to western North America, their popularity among fishermen has led to their spread across the world. These introductions can cause imbalances within bodies of water where the trout is not native. Besides eating the eggs and young of native fish, the rainbow trout may also out-compete native fish for habitat and food.