What is the heaviest species of bony fish?

What is the heaviest species of bony fish? The answer is the giant sunfish, Mola alexandrini.

The giant sunfish, also called the bumphead or southern sunfish, is the largest living ray-finned bony fish by recorded mass. A specimen found near the Azores in 2021 weighed approximately 2,744 kilograms.

For many years, the better-known ocean sunfish, Mola mola, was identified as the record-holder. Later taxonomic research clarified that some record specimens had been misidentified and actually belonged to Mola alexandrini.

The species has the characteristic truncated body shared by molas, with the tail replaced by a clavus formed from modified dorsal and anal fins. Its enormous size makes it a notable exception among modern bony fishes.