Headshot of a whale shark(Rhincodon typus), photographed while snorkeling off the coast of Mafia Island in Tanzania. Whale sharks are the biggest sharks and the biggest fish in the world. Note, that they are NOT whales but feed like whales do. The filter feeder sieves enormous amounts of plankton to eat through its gills as it swims. They are harmless to people and usually indifferent to divers.