Tag Archives: Mola Mola

Mola Mola Song

The Ocean Sunfish also known as the Mola Mola is perhaps the most strangely intriguing fish in ocean. Its appearance is more alien like than anything else though it isn’t from out of this world. The Mola Mola belongs to the class Osteicthyes that means bony fish. This differs from chondricthyes, which are fish that are made of cartilage like sharks or rays. The Mola Mola is particularly interesting fish. Though it is a bony fish that belongs in the order tetraodontiformes, which includes puffer fish and triggerfish, it lacks several structural features that are prominent on most of their fish cousins. The most glaring absence is the caudal fin (tail fin) and the presence of elongated dorsal and anal fins, which it uses to swim. They also lack a swim bladder, which is a special organ in bony fish that helps them maintain neutral buoyancy. Ocean Sunfish have buoyant skin to help them float which is very beneficial since Mola Mola have the potential to be large. They are the heaviest of all bony fish with some specimens recorded weighing over 5,000 pounds. To grow to such a size one would think that Mola would be carnivores with a high protein diet but instead they are pretty passive eaters that mainly eat jellies that they come across in the ocean. Some specimens have been found to have brittle stars and pieces of fish in their stomachs indicating that they may have a broader diet than previously thought.

mola mola flat

The Mola Mola is received the name Sunfish because their tendency to lay flat at the surface basking in sunlight. Historically they were thought to be planktonic and only go wherever the ocean currents would take them but Mola Mola are actually very strong swimmers that have the ability to dive to fairly deep depths. Sunfish have been observed swimming as deep as 600 meters. One theory that has yet to be proven is that Mola Mola bask at the surface to warm themselves up after extremely deep dives. They have also been known to swim beneath kelp rafts to let fish such as senoritas eat ecto-parasites that attach to their skin. On occasion they will even let birds like seagulls peck the parasites from their skin.

mola mola skin

Mola Mola are found in every ocean except the arctic but breeding grounds or seasons have not been determined. Mola Mola do however lay over 300,000,000 million eggs per individual. The sunfish lays more eggs than every other know vertebrate.

Mola Mola have very few predators. Sharks, Orcas, and Sea Lions have been known to prey on Mola Mola but do not do it habitually. Humans do not regularly fish for Mola and there isn’t a market for them in most parts of the world. Humans are however the biggest threat to Mola due to bycatch from commercial fishing operations around the world.

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The Marvelous Mola

Mola2Mola Mola’s are definitely one of the strangest looking fish found in our oceans. Mola’s got their name due to the very distinct shape of their body, in Latin the word Mola means “millstone.” They have a very rounded body with very pronounced dorsal and anal fins.

An average adult Mola will reach about 6 feet from snout to tail and about 7 feet from the tips of the dorsal and anal fins. They also weigh an average of about 2,200 pounds however some molas have even been documented weighing in at a massive 5,000 pounds making them the heaviest of all bony fish!

Nicknamed the ocean sunfish these enormous fish are frequently seen basking in the sunlight near the surface. Because Mola’s lack a swim bladder, have a very thick layer of low-density gelatinous tissue under their skin, as well as a degenerate cartilaginous skeleton they are neutrally buoyant in the water. This allows Mola’s to move with ease both horizontally and vertically in the water column.

Mola’s utilize both their dorsal and anal fins as their primary way of locomotion – they essentially use these fins as a pair wings. Although they may look like slow awkward swimmers it has been documented that the combination of their “wings” allow them to swim long distances, dive to incredible depths, breach out of the water, and even swim up to speeds of almost 0.4 to 0.7 meters per second! How insane is that!

Screen Shot 2016-05-26 at 12.14.33 PMBecause these fish can get up to such a massive size females produce more eggs than any other vertebrate on our earth. It is estimated that females carry more than 300 million eggs! Mola’s are in a spiky star-shape when they are first born giving planktonic Mola larva extra protection during their first few weeks. As they continue to grow larger and stronger these spikes begin to disappear. During their first year it is estimated that Molas will gain an average of 2 pounds per day. The Monterey Bay Aquarium once observed a Mola that gained about 822 pounds in just 15 months. So what do these awesome fish eat in order to get to such large sizes?

A Mola’s favorite snack are the gelatinous zooplankton that drift with the ocean currents. In particular they love to prey upon jellies, Portuguese man-o-war, by-the-wind sailors, as well as salps.

Ocean sunfish love to bask at the surface of the water to thermoregulate as well as catch prey. However they also chill in the surface of the water for another extremely important reason. Overtime Mola’s become infested with tons of parasites. More than 50 species of parasites have been documented both on and within molas. In order to combat these pesky parasites they have molas have formed symbiotic relationships with cleaner fish and even birds. Some have even been documented breaching 10 feet out of the air, landing on the surface with a forceful splash in hopes of removing these parasites.

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Written By: Alex Feltes


Leisher, Craig. Mola Mola: The Weirdest Fish in the Ocean? Cool Green Science. 2014

Love, Milton S. Mola Mola. Certainly More than You Want to Know About the Fishes of the Pacific Coast. 2011.


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