The ocean sunfish (Mola mola) is the heaviest bony fish in the world, with an average weight of 1000 kilograms. The species is native to tropical and temperate waters around the globe. It resembles a fish head without a tail, and its main body is flattened laterally. Sunfish can be as tall as they are long, when their dorsal and anal fins are extended.
Sunfish live on a diet that consists mainly of jellyfish. As this diet is nutritionally poor, they consume large amounts in order to develop and maintain their great bulk. Females of the species can produce more eggs than any other known vertebrate. Sunfish fry resemble miniature pufferfish, with large pectoral fins, a tail fin and body spines uncharacteristic of adult sunfish.