05 Mar Nusa Penida is now home to the world’s largest bony fish – the Mola Alexandrini (previously known as Mola ramsayi)
A research paper published in January 2018 was conducted by Japanese fish experts examining accounts of sunfish sightings and captures going back 500 years. They discovered the world’s heaviest bony fish ever caught is a Mola alexandrini – or a bump-head sunfish, and not, as originally thought, a member of the more commonly known Mola mola species.
Thus, Mola ramsayi which was thought to be the species we commonly see at Nusa Penida is actually a Mola alexandrini and is considered the world’s largest bony fish! This species has a large swelling on its forehead, hence its common name: the bump-head sunfish. It also has a giveaway bump on its chin and a differently shaped tail which makes it easier to differentiate from the other two mola species. One of the researches Etsuro Sawai at Hiroshima University in Japan argues that Mola alexandrini is the same as Mola ramsayi, and that Mola ramsayi (the Mola we see at Nusa Penida) should now be called Mola alexandrini because that name was used first.