The ocean sunfish, Mola mola, is the heaviest known bony fish in the world. It has an average adult weight between 247 and 1,000 kg (545–2,205 lb.)! The species is native to both tropical and temperate waters around the globe, and it can frequently be seen sunbathing at the surface of the sea, which gives it its name in English. In Spanish it is called "pez luna" - moon fish, due to its round shape. It resembles a fish head with a tail, and its main body is flattened laterally. Females of the species can produce more eggs than any other known vertebrate,... up to 300,000,000 at a time!
The diet of sunfish consists mainly of jellyfish, and because jellyfish are nutritionally poor and sunfish are usually enormous, they need to consume very large amounts. They are a great natural way of keeping populations of jellyfish under control!
Sunfish can easly be seen in Mediterranean waters, especially during the warmer summer months, when they spend long periods at the sea surface. In Ireland they can be spotted in July and August. They are easy to see because their fins tend to stick out of the water. Since they are slow swimmers they tend to have many parasites on their skin; it is common to see gulls sitting on them to eat those parasites ...but sometimes they also bite the eye on that side!