Heaviest bony fish

The heaviest bony fish are the sunfish (genus Mola), with adults obtaining an average length of 1.8 metres (6 feet) and weighing around 1,000 kilograms (2,200 pounds). The heaviest specimen on record is a deceased bump-head sunfish (Mola alexandrini) found off Faial Island in the Azores, Portugal, on 9 December 2021; it weighed 2,744 kilograms (6,049 pounds) and measured 3.25 metres (10 feet 8 inches) in total length and 3.6 meters (11 feet 9 inches) between the fin tips. Its dimensions were detailed in a study published in the Journal of Fish Biology on 11 October 2022.

This surpasses another specimen of bump-head sunfish caught off Kamogawa, Chiba, Japan, in 1996; it weighed 2,300 kg (5,070 lb) and measured 2.72 m (8 ft 11 in) in length. It was previously thought to be an ocean sunfish (M. mola), but this was refuted in a study by Hiroshima University, the University of Tokyo and Murdoch University published in the journal Ichthyological Research on 5 December 2017. The same study also contested that the bump-head sunfish (M. alexandrini) is synonymous with the southern sunfish (M. ramsayi).

The name Mola comes from the Latin meaning millstone in relation to this animal's rounded body shape. Sunfish are found in all oceans in tropical or temperate climates and feed on zooplankton, small fishes and algae.

The Azores sunfish was documented in a collaborative paper contributed to by the Atlantic Naturalist Association, the University of the Azores, the University of Lisbon (all Portugal), the Auckland War Memorial Museum Tamaki Paenga Hira (New Zealand) and Dr Etsuro Sawai of the Ocean Sunfishes Information Storage Museum (Japan), led by PhD student José Nuno Gomes-Pereira (Portugal).

Photo credit: Gomes-Pereira et al. 2022