This week we saw 5 Mola Mola on 1 dive in Lembongan so I thought that I would find out what a Mola Mola is, and the first thing I discovered is that the Mola Mola is the heaviest bony fish in the world!! (sharks and rays can be heavier, but they’re cartilaginous fish).
The Mola Mola, or ocean sunfish, resembles a big floating blob, and the adult has an average weight of 1,000 kg and is 180cm long (250cm fin to fin).
They are found in temperate and tropical oceanic waters around the world, but they come closer to shore from July -mid November in Bali and are seen at a number of dive sites around Nusa Lembongan and Penida, often daily.
They can swim to depths of almost 600m, but are frequently seen basking in the sun near the surface, often mistaken for sharks when their huge dorsal fins emerge above the water. One of the reasons for being so shallow is that they can become so infested with skin parasites that they will often invite small fish or even birds to feast on the pesky critters. They will even breach the surface up to 10 feet (3 meters) in the air and land with a splash in an attempt to shake the parasites.
They are clumsy swimmers, waggling their large dorsal and anal fins to move and steering with their rear fin (called the clavus). Their teeth are fused into a beak-like structure, and they are unable to fully close their relatively small mouths, hence their diet mainly consists of jellyfish, though they will eat small fish and huge amounts of zooplankton and algae as well. They are harmless to people, but can be very curious and will often approach divers.
Their population is considered stable and they possess relatively few predators, although they frequently get snagged in drift gill nets and can suffocate on sea trash, like plastic bags, which resemble jellyfish.
Here is a video from National Geographic showing them off:
Se them for yourself and Dive with us in Lembongan, Bali