Mola mola, also known as ocean sunfish, captivate ocean lovers with their impressive size, peculiar shape and fascinating behaviours. From their daring diet (jellyfish anyone?) to their extraordinary adaptations, read on to discover our top ten mola mola facts…
A fish of many names
You may have heard mola mola referred to as sunfish, moonfish or basketfish. They're known by various names depending on the culture. In some places, they're also seen as symbols of good luck, and in ancient Japan, they were even used as a form of tax payment during the Edo period.
Origins of the name
Have you ever wondered where the name mola mola comes from? The scientific name mola mola is derived from Latin, which means milestone, referring to the mola mola's round shape.
The mola mola family
Mola mola belong to the molidae family (which consists of three genera: mola, ranzania and masturus) and there are three recognised species: mola alexandrini, mola mola and mola tecta. Mola alexandrine are most commonly observed around Nusa Penida, an island off the coast of Bali renowned for its dreamy underwater landscapes, thrilling currents and diverse marine life.
The early life stages of a mola mola
Female mola mola can produce up to 300 million eggs at one time, one of the highest known egg counts among fish. After a mola mola hatches, it joins a school as a juvenile, where it grows rapidly to around 15mm and develops protective spikes on its body. As they mature and grow past 37mm, they lose their spines and leave school to go and live alone or sometimes with another mola mola…
From tiny hatchling to ocean giant
Another fascinating fact about mola mola is that they can grow larger than many marine animals, reaching up to ten feet from fin tip to fin tip - surpassing some smaller whale species. As they grow, their weight increases by about 60 million times from when they hatch. By adulthood, they can weigh as much as 2,200 pounds, making them one of the heaviest bony fish in the ocean.
Flat appearance
Ever wonder why mola mola look like they've been flattened? Their odd appearance is due to several adaptations that help them evade predators. Their wide, flat bodies allow them to blend in with the ocean surface. They can also camouflage themselves to their surroundings by changing their skin colour and patterns, which helps them avoid detection from predators such as sharks.
Daring diet
Mola mola primarily eat jellyfish, although they occasionally enjoy a more varied menu, including other gelatinous organisms like zooplankton and salps, as well as squid, crustaceans and algae. They break their food down into smaller pieces using their two beak-like teeth which are specially adapted for feasting on these soft-bodied species. As mola molas have very slow metabolisms, it can take several days to digest their food fully.
Sun-loving creatures
A fact about mola mola that we love is that, like many of us, they enjoy basking in the sun. After hunting at depth, they return to the ocean's surface and bathe in the sun's warmth to regulate their body temperature. This is why they are often seen floating just below the ocean surface.
Climate change indicators
Mola mola are especially useful to scientists. Their migration patterns, driven by changing ocean temperatures, make them valuable indicators of climate change. As a result, they are monitored for insights into climate change and the health of ocean ecosystems.
Noisy neighbours
Our final fact about mola mola is that despite their docile nature, they can be rather noisy creatures. They often grunt as a form of communication, so you wouldn't want to have one for a neighbour!
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