The gentle giant of the open ocean
The Mola mola, also known as the ocean sunfish (Mola mola), is one of the heaviest bony fish in the world. Found in temperate and tropical oceans across the globe, this massive fish can weigh over a ton, yet moves with surprising grace through the water using its tall dorsal and anal fins.
Despite its unusual shape—flat and round like a floating head with fins—Mola mola is a peaceful filter-feeder. Its diet consists mostly of jellyfish, small fish, plankton, and algae. Often seen basking near the surface, it appears to soak up the sun, which may help regulate its body temperature after deep dives.
Key Facts
- Scientific Name: Mola mola
- Native Region: Temperate and tropical oceans worldwide
- Notable Trait: Enormous size and distinctive flattened body with long dorsal and anal fins
- Diet: Jellyfish, small fish, plankton, algae, and occasionally squid
- Size: Adults can reach 1.8–3.3 meters (6–10 feet) in length
- Lifespan: Up to 10 years in the wild, sometimes longer in protected areas
Habitat
Mola mola inhabit open ocean waters from the surface to depths of over 600 meters (2,000 feet). They prefer temperate and tropical zones where jellyfish and plankton are abundant. Often spotted floating near the surface or swimming slowly with fins outstretched, Mola mola are highly migratory and can travel long distances across oceans.
Despite their size, they are vulnerable to predators such as sea lions, orcas, and large sharks. Basking at the surface may also attract seabirds that help remove parasites from their skin—a unique example of ocean teamwork.
Behavior
Mola mola are solitary or found in small groups. They are slow swimmers but highly efficient at filtering food from the water. Their massive size and shape make them a challenge for predators, but they still rely on vigilance and occasional deep dives for safety.
They are known for “sunbathing” at the surface, often lying sideways in the water. This behavior may help regulate body temperature after hunting at colder depths. Juveniles are often found closer to coastal areas and gradually move into deeper waters as they grow.
Mola mola are generally peaceful and pose no threat to humans, making them a favorite among divers and marine enthusiasts who encounter them in the wild.
FAQs
Why is the Mola mola called the ocean sunfish?
Because it often basks at the surface of the water, appearing to soak up the sun. Scientists think this helps warm its body after deep dives into colder water.
How does a Mola mola move through the water?
Unlike typical fish, it uses its tall dorsal and anal fins to “fly” through the water, with its tail used mainly for steering. Despite its bulk, it is surprisingly agile for short bursts.
Do Mola mola have teeth?
They do, but their teeth are fused into a beak-like structure perfect for crushing jellyfish and soft prey. They are not for biting large objects or defending themselves.
Can Mola mola jump out of the water?
Yes! They are occasionally seen leaping high, possibly to remove parasites, communicate, or escape predators. It’s a rare but spectacular sight.
How many babies does a Mola mola have?
Females can produce up to 300 million eggs at once, making them the most fecund of all vertebrates. Only a tiny fraction survive to adulthood, but their sheer numbers help the species persist.
Do they have predators?
Despite their size, Mola mola can be eaten by orcas, large sharks, and sea lions. Their thick skin and size give them some protection, but vigilance is still important.
