River otters' main source of food is fish, but otters are opportunists by nature and will eat a wide variety of foods. With the ability to smell concentrations of fish and their high metabolisms, otters spend most of their time hunting for their next meal.
Outside of fish, river otters will also eat crustaceans, insects, birds, oysters, shellfish, turtles and a number of other aquatic life. These furry water lovers hunt mostly at night, following the scent of fish even into urban areas. It is not uncommon for anglers to have to fight river otters for their bait. While otters are mostly carnivores, they will eat the corn that is used to fish for trout, especially along rivers that are stocked with hatchery fish.