The largest fish in the world, the whale shark, is an endangered species found in most of the world’s tropical waters. Like the megamouth sharks and the basking shark, whale sharks are filter feeders and their diet consists almost exclusively of plankton. Because of this they’re completely harmless to humans, and diving with whale sharks has become a popular ecotourism attraction in several countries. The largest individuals can weigh over 30 tonnes and give birth to 300 pups.