Mahi-mahi (also known as the common dolphinfish or dorado) are some of the most impressive swimmers of the ocean. They can grow over four feet in their first year and a half, swim at speeds over 40 miles-per-hour, and make massive migrations across the ocean, sometimes up to 1,864 miles (3,000 km) in one month. When housed in an aquarium they are fed in the same manner as captured sharks— researchers must ensure they are always happily full, otherwise, they are quick to turn on each other and become cannibalistic.