Otters are carnivorous animals and eat mainly fish. They are known for being skilled hunters and are capable of catching a variety of fish species, including salmon, trout, and eels. Otters also eat other aquatic animals such as crayfish, crabs, and frogs. They have a high metabolism and require a significant amount of food to sustain their energy levels. Some otter species, such as sea otters, also eat shellfish and other marine invertebrates.