Sharks are the largest type of fish in the sea. They are often thought of as mindless killers but actually mostly only attack when threatened.
The largest shark (and fish) in the sea is the whale shark. It diets on small fish, krill, plankton and small invertebrates.
The fiercest is the great white shark. It diets on large fish such as tuna, rays, other sharks and very, very rarely humans.
The smallest shark is the dwarf lanternshark. Scientists have not studied it close enough to find out about their diet.