Heaviest fish

What to remember

The heaviest fish turns out to be a plankton eater. The whale shark has a known maximum mass of 21.5 tonnes (47,000 lb), and the largest reliably recorded individual was 18.8 m (61.7 ft) long.

This slow-moving carpet shark is a filter feeder, taking in plankton, krill, fish eggs and small schooling fish such as sardines and anchovies. It is harmless to humans. The only living species of the genus Rhincodon, it was classified as Rhiniodon before 1984.

The whale shark and the basking shark outstrip every other fish species by a wide margin in both weight and length. Only the extinct Otodus megalodon was bigger. Marine mammals such as the blue whale do not count, as they are not fish.