Botos eat a broad range of food, including up to fifty different species of fish. Most of the fish they eat are from 8 to 12 inches (20 to 30 centimeters) long, although they are able to eat fish as long as 31 inches (80 centimeters). During the rainy season, the forests flood, fish swim into the flooded areas to eat seeds and fruits, and botos follow the fish. They are able to move easily in this shallow water, because they are so flexible and they have a well-developed sense of echolocation. When the water level starts to fall, the fish and the botos return to the deeper main channel.
Along the South American rivers where the botos live, the dolphin is associated with unhappiness. The boto is said to turn into a man at night, one who seduces young girls and impregnates them. The boto is also said to turn into a lovely girl who leads men into the river and takes them away forever. Seeing a boto is supposed to be bad luck and burning boto oil in a lamp is supposed to make people who look at the lamp go blind. The boto's connection to bad luck and unhappy events may have helped save it, since the boto has never been hunted for oil or food.
Botos also eat small turtles, mollusks (hard shelled animals like clams), freshwater shrimp, and crabs. Other species of dolphins have only sharp cone-shaped teeth. Botos have this type of tooth, but also have some teeth that are modified for grinding. This allows them to eat a wide variety of food.