Common Mola: Characteristics, reproduction, habitat and more…

The sea is full of very curious animals, one of them is the Ocean Sunfish or common mola (Mola Mola), which is the heaviest of the bony fish that exists today. It belongs to the Molidae family, and is a pelagic fish of the Tetraodontiformes order to which the puffer fish, the hedgehog fish and the Tijas also belong.

This fish shares with them many characteristics and has a somewhat disturbing aspect… learn today everything about this fish in this complete post… .

The genus of this fish is Mola and hence comes its most significant name Mola Mola which is also its scientific name this word translated into Spanish is Teeth.

Taxonomy 🐟

Kingdom: Animals Phylum: Chordata Class: Actinopterygii  Order: Tetraodontiformes Family: Molidae Genus: Mola

Actinopterygii 🐟

Actinopterygies (Actinopterygii, from the Greek ακτινος aktinοs, «ray» and πτερυγιον pterygion, «fin») are a class of bony fish (Osteichthyes *).

They are the dominant group of vertebrates, with more than 27,000 current species, and have developed adaptive strategies that have allowed them to colonize all kinds of aquatic environments, both marine and freshwater and brackish.

The best known species of fish belong to this group: trout,(int) salmon, sardines, pike, perch, herring, tuna, cichlid, flatfish, carp, eels,(int) etc.

Morphology 🐟

The main feature of actinopterygia is the possession of a skeleton of bone spines on its fins. In fact, the term Actinopterygii means «radiated fins.»

Their cartilaginous skull (partly calcified) is covered by dermal bones, and their single pair of gill openings is covered by an operculum.

Actinopterygii are also characterized by having ganoid scales (autapomorphic character, that is, exclusive to the group)  with ganoine, spongy bone tissue and laminar bone tissue.

In today’s fish, the ganoid scale is reduced (leptoid) by presenting two types: cycloid and ctenoid, in which only laminar bone tissue is present, without ganoine or spongy. We invite you to read our article the anatomy of fish to learn about such an intersting topic.

Let’s learn more about them

Common Mola: Main Characteristics 🐟

This fish has unique characteristics that make it very special. One of its peculiarities is that it seems that it’s only a head without a tail. We are going to study in this section the general appearance of this fish.

The common mola  is native to temperate and tropical waters around the world.

He usually swims actively between different levels of water depth.

In this way, it generates a particular swimming pattern, related to the time of day and the water temperature.

Jellyfish and salps make up 15% of the common mola diet. In addition, it consumes larvae of fish, squid, small fish, crustaceans and algae.

Body 🐟

The common mola’s body is large and flattened laterally. The spine is short and has fewer vertebrae in relation to other fish.

Despite descending from bone ancestors, its skeleton is made-up in a high proportion, by cartilaginous tissues.

This characteristic, together with the thick layer of slightly dense and gelatinous tissue, contributes to the buoyancy of the common mola which constitutes a very important aspect, due to its lack of swim bladder

Fins 🐟

The common mola lacks caudal fin, as a result of the degeneration suffered by the spine during evolution. Instead, it has a rigid and wide lobe, called clavus which extends from the posterior margin of the dorsal fin to the posterior end of the anal.

In addition, it consists of 12 rays and ends in several rounded ossicles. While swimming, the fish uses the clavus as a rudder.

Face 🐟

The mouth is small, compared to the dimensions of its body while its teeth are fused, forming a beak-like structure. In addition, it has pharyngeal teeth, located in its throat.

Size 🐟

The common mola can measure up to 3.1 meters long and 4.25 high while its weight is around 2.3 tons. Sexual dimorphism is exhibited in this species, with males being smaller than females.

Skin 🐟

During its adulthood, the common mola usually has a gray, brown or white coloration.

However, some specimens have mottled skin, a pattern that could be specific to each region. The coloration is usually darker dorsally, fading in a lighter shade towards the ventral area.

The skin is rough and thick, measuring up to 7.3 centimeters wide. In addition, it’s made-up by cross-linked collagen and lacks scales. Externally it has denticles and a layer of mucus.

Let’s meet it

The Common Mola’s Genome 🐟

Due to its large size, the shape of its body and its fast growth, the common mola has been subject of numerous investigations in order to find out the details about the genomic changes that gave rise to these characteristics.

In relation to growth, some receptor genes had a positive selection, although the development factors IGF-1 and GH do not show changes. This indicates that the GH-IGF1 axis may have played a decisive role in the body size and growth rate of this species.

As for the cartilaginous skeleton, the specialists identified several genes that encode the collagen, which were evolutionarily selected positively. In addition, it was shown that GH-IGF1 factors have functions in regulating the development of cartilage and bone.

Let’s learn about this inetersting topic

The Perfect Name 🐟

In German, common molas are called «schwimmender kopf» – literally «swimming head». In Polish they are called «samogłów» – «lonely head».

Some Hawaiian names for them include «kaumakanui» – «eyes stuck on it» – and «kunehi apahu» – «it’s been cut off». In Afrikaans, Albanian, Icelandic, and Russian, they are «maanvis», «peshku hënë», «tunglfiskur», «луна-рыба» – «moonfish».

In Hebrew they are «דאג השמש» – «sun watcher». In Taiwan, they are known as «the fish that looks like a toppled car».

Their modern scientific name Mola was coined by Swedish naturalist Carl Linnaeus in the 1700s. Linnaeus noted that when they basked in the sun, they looked like large, gray millstones – «mola» in Latin.

Common Mola: Habitat and Distribution 🐟

The common mola is distributed in the temperate and tropical waters of the Indian, Atlantic and Pacific oceans. It’s also found in the North Sea and in the Mediterranean.

Sightings in the North Sea and in the British Isles occur during the summer, especially in the months of June and July, when the water reaches a temperature between 13 and 17 ° C.

In the eastern Pacific, it lives from Canada to Chile and Peru and even throughout the Indian Ocean, encompassing the Red Sea. Thus, this species is located from Japan and Russia to New Zealand and Australia.

As for the eastern Atlantic, the common mola can be seen from Scandinavia to South Africa, and occasionally in the Baltic Sea. In relation to the western Atlantic, it’s found from Argentina to Canada, including the Caribbean Sea and the Gulf of Mexico.

Habitat 🐟

The common mola prefers the open ocean, but it can occasionally enter reefs and seaweed beds to eliminate its parasites.

There is a belief that the sunfish spends much of its time on the surface.

However, recent research indicates that it’s an epipelagic species, whose depth range covers up to 400 meters. However, it can swim up to 600 meters.

The temperature of the water where it lives should be above 10 ° C.

If this fish remains a long period of time in water with temperatures below that value, it may become disoriented and even die.

Movement patterns 🐟

Adult common molas are active swimmers, who perform directional and horizontal movements independent of the current. In addition,  they have a specific pattern of water use, according to depth levels.

Thus, during the night common molas tend to locate in the hottest layer and during the day they swim vertically repeatedly between the surface and the deepest and coldest waters.

Although this depth range changes over time, the common mola continues to move from top to bottom in the water column.

In terms of behavior, the Mola mola can surface and “sunbathe”. Thus, it can stand on its side and beat its fins. Researchers associate this behavior with a method to warm the body, after a deep and cold water immersion.

During these vertical movements the search for dams can be carried out, thus being able to locate the maximum abundance of these.

Feeding Habits 🐟

Formerly it was thought that the diet of the common mola was based exclusively on jellyfish. However, recent studies indicate that it’s a generalist predator which is able to adapt to the availability of resources offered by the environment where it lives.

Small fish, squid, fish larvae, crustaceans, salps, mollusks and jellyfish, among which are Rhizostoma, Cyanea capillata and Chrysaora hysoscella make up the diet of this species.

Moreover, it also eats sponges, small fish, flounder  ctenophores, snake starfish, Portuguese frigates and eel larvae found in deep water.

As for plant species, the common mola ingest various types of zostera, plankton, algae  and eel grass.

This wide range of food indicates that Mola mola forages at different levels of the ocean. Thus, they do it on the surface, among the floating weeds, in deep waters and on the seabed.

Research works, based on the study of stomach contents in young and adult species, indicate that there are differences in their diet. The diet of adult specimens is mainly made-up of gelatinous zooplankton, while the young are mostly benthic feeders.

Eating methods 🐟

In general, this kind of foods is poor in nutrients. Because of this, the animal is forced to consume large amounts of food daily, to meet its metabolic needs.

The common mola has special adaptations to eat jellyfish Which have a thick skin that provides protection against the numerous stingers or nematocysts .

Mola mola has a small mouth and its teeth are fused, forming a sort of beak which helps then to cut into pieces the hardest dams, before eating them absorbing and spitting out the jelly-like ones.

In addition, common molas have pharyngeal teeth in their throat which section the food into smaller pieces before it reaches the stomach.

Reproduction 🐟

Mola mola reaches sexual maturity when it’s between 5 and 7 years old. This species is considered the most fertile among all vertebrates, since the female spawns around 300 million eggs.

Although data on mating are scarce, the observed behaviors infer the existence of a courtship. After this stage, the female releases her eggs in the water, which are fertilized externally by the male’s sperm.

Spawning areas are the North Pacific, the South and North Atlantic and in the Indian Ocean. Fertilization occurs between August and September.

Although the female spawns a large number of eggs, these are small and are scattered in the water. This makes the chance of survival low.

Once the egg is fertilized, the embryo is transformed into a small larva, which has a tail. This structure disappears after hatching. In relation to the development of the egg, it’s asynchronous, which suggests that spawning is multiple.

Eggs Development 🐟

The eggs measure around 0.13 centimeters in diameter and the larva 0.25 centimeters, so the growth of this species is amazing.

The growth rate can be between 0.02 and 0.49 kg / day, and can reach 0.82 kg / day.

This allows the common mola to quickly reach the great weight that characterizes it.

Mola mola has two larval stages, before reaching the adult stage. In the first phase, the larvae have a round shape and spines, which protrude from the body.

In addition, they have pectoral fins and a caudal fin. During the second stage the spines disappear and the tail is reabsorbed.

The young are mobilized in groups, to protect themselves from predators. However, when they grow up, the moonfish becomes lonely.

Behavior 🐟

Cleaning station

More than 40 species of parasites can live on the skin of the sunfish, which leads the animal to try to eliminate them from its body. Some of the most frequent species are Accacoelium contortum, Thalasoma lunare and Labroides dimidiatus.

In temperate regions, there are cleaning fish, usually located in those areas where drifting algae are found. These are responsible for removing the parasites that live on the skin of Mola mola.

When the sunfish lives in the tropics, it receives the help of those fish that are in the coral reefs.

In Bali, this species frequently approaches the cleaning stations on the reefs, where school standard fish clusters (Heniochus diphreutes) are found. These eat the organisms that live in the skin of the sunfish.

When this fish emerges to the surface, it positions itself on its side or projects its dorsal fin above the water, allowing seabirds to feed on the ectoparasites of their skin. In southern California, seagulls usually fulfill that function.

How Common Mola Swims? 🐟

Mola mola has a short spine and lacks caudal fin. Due to these morphological changes that he has evolutionarily undergone, he has a particular swimming way which is different from that based on trawling, typical of the vast majority of bony fish.

The thrust necessary to move is caused by the synchronous movement of the anal fin and the dorsal. This force is based on elevation and resembles the flight of birds.

This swimming way could involve adaptations in the nervous system, related to the musculoskeletal system. In this sense, studies of the anatomy of this fish show that their peripheral nervous system presents differences with other fish of the order Tetraodontiformes.

How long Common Mola Lives?

The life expectancy of this species in captivity is ten years and its longevity is still unknown when in nature.

In its wild state, its growth rate has not been determined although it’s known from an investigation of a young specimen located in Monterey Bay Aquarium Monterrey in California, which increased its weight from 26 to 399 kilograms and reached a height of approximately 1.8 meters in just fifteen months

Predators 🐟

Although Mole Mole fish is large and has thick skin that can deter many fish from attacking it, it still has some predators.

The youngest specimens are the ones that present the most vulnerability, they can also be attacked by bluefin tuna, also gold, since when they are large adults they are prey for killer whales, sharks, and sea lions.

The latter have a very aggressive attitude towards this species. they hunt it as a sport, they tear its fin and abandon the defenseless fish but still alive, it will later die on the bleeding seabed.

Here they are again

Common Mola and Human Beings 🐟

Let us learn in this section everything related to the correlation of humans with the moonfish or Mola or Mola.

Social relationship

Its large size is intimidating for many people, but this fish is usually docile and doesn’t represent any inconvenience to divers who are studying the ocean.

Few isolated cases have been reported when a common mola jumped and fell on a four-year-old boy which happened in the city of Pembrokeshire located in Wales.

This species is usually found in diving areas and it’s said that divers who travel through such places have become accustomed.

These fish are more dangerous for navigators and it’s not because they cause physical damage to people but because they usually collide with small boats and due to their large size and weight they cause significant damage when stuck in the propellers.

It’s worth noting that in some regions fishermen consider it a worthless bait thief, these people cut the animal’s fins to use as bait and leave it adrift.

More information

Currently, many issues associated with the Mola Mola are ignored, although studies are being carried out to determine aspects such as its biology and population through aerial shots taken by satellites.

Even some fans have dedicated themselves to observing the species to collect their data.

A recent study indicates a decrease in its population which is believed to be caused by the frequency of by-catches and the increase in meat consumption.

Common Mola In Captivity 🐟

The Mola Mola is not common in aquariums because it’s very difficult to take care of them, although there are aquariums where they can be observed especially in Japan at the Kaiyukan Aquarium that is located in the Osaka area where the mola fish is the biggest attraction along with the whale shark.

For its part in Europe at  the Lisbon Oceanic in Portugal, there is also a specimen exposed in its main tank.

In Spain there are specimens in the Aquarium of Barcelona and L’Oceanogràfic which is located in the city of Valencia.

Finally in Poniente in the same country is the Gijón aquarium which also has specimens of Mola Mola or Mola Mola.

The first specimen conserved in an aquarium took place in Monterrey in the city of California in the US country EEUU in 1986. This aquarium is called Monterey Bay Aquarium. This species had never been kept in captivity on a large scale, and it was necessary to innovate and create its own system for capturing, feeding and controlling parasites.

As of 1998, the problems associated with the species had already been overcome and a specimen could be maintained for more than a year.

This was released when its weight increased more than fourteen times since that time. The common mola became a permanent attraction of its tank called Outer Bay.

The largest specimen they kept in the aquarium was sacrificed at the beginning of 2008 because it went through a long period of illness and its release was not possible.

Care 🐟

These fish move very slowly, the caretakers must be careful that the common mola are not harmed by colliding with the walls of the aquarium tank.

In some small tanks these guardians place a vinyl curtain that surrounds the cube-shaped tank to prevent the fish from hitting the sides. However,  it’s advised that the fish has enough space so that it can move comfortably in big circles.

The tank must be deep enough so that the fish can accommodate without any problem.

It’s worth to point out that common molas have a minimum height of three meters and it’s important to teach them to eat from the hand of their caretakers or through the tip of a bar since if they have faster and aggressive fish as neighbors they could run out of food.

This is really difficult and is considered a challenge for managers.

Common Mola at the Aquarium of Barcelona

Viral Video 🐟

Michael Bergin and Jason ‘Jay’ two navigators posted on Facebook on September 17, 20015 a video of the common mola which went viral quickly being one of the most popular in 2015.

It was shared twenty eight thousand times and achieved three and a half million views; in the ranking of the 100 most impressive videos of 2015 achieving a great  impact on the internet.

The creators of this popular video were interviewed by some news portals and TV shows, Michael told him that he had no idea what fish the Boston Globe was about, they are known on the YouTube platform as the Viral Fish Guys

The American comedian, actor, presenter and screenwriter Jimmy Kimmel presented them on his Jimmy Kimmel Live program belonging to the ABC television network which is  one of the most popular in the since 2013.

This appearance gave more publicity to your video further increasing its views and publications.

Watch this interview on the Jimmy Kimmel live program along with part of the viral video in this video the original language is in English and the interview is via Skype.

They comment that at the beginning they thought it was a turtle or a whale calf at the time of its publication on Facebook they affirmed that they did not know what it was after seeing the fish they warned the coast guard of the appearance of the fish they did not manage to capture it.

Here it’s