The Mola mola, or common mola, is the heaviest known bony fish in the world. It has an average adult weight of 1,000 kg. Sunfish live on a diet that consists mainly of jellyfish, but because 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.