Sunfish is a popular fish known for its large body and charming face. Its unique form, unlike that of ordinary fish, has an impact that is unforgettable once seen.
Although it is a well-known fish, its ecology is still shrouded in mystery. Let’s take a closer look at the ecology that is currently known.



~ Basic information. ~

Tetraodontiformes Molidae Sunfish genus.

Length:1m to 3m or more.


Sunfish are found in oceans around the world, mainly in warm tropical and temperate waters.

They are the largest bony fish in the world, and some bump-head sunfish, which are part of the sunfish family, are over 3 meters long. There is still much to be learned about them as they move between the surface of the open ocean and the deep sea. There may be even larger individuals out there that have yet to be discovered.

The body is covered with many parasites, and research on parasites is also underway. Parasites also attach to their eyes, making it difficult for them to see. Because their eyesight is poor, it is a well-known story that they collide with aquarium tanks.

For a while, it was thought that there were only two types of sunfish. However, in 2017, a new species was discovered and became a hot topic. It was named “Hoodwinker ocean sunfish” because it had been hidden among existing species, and its English name and scientific name were also named after “hiding”.




Sunfish’s Q&A.

What is the origin of the name sunfish?

“Sunfish” is the English name for the fish, but in Japanese it is called “manbou”. This time, I will introduce the origin of why it is called “manbou” in Japanese.

The name “manbou” uses the kanji for “manbou” and “engyo”. It is said that both “man” and “en” come from the roundness of the sunfish’s appearance, and “bou” and “gyo” are said to have changed due to the distortion of the pronunciation of “bou”.

Next, let’s take a look at how sunfish is called overseas. The scientific name is “mola mola”, and “mola” means “millstone” in Latin. It seems that the round body of the sunfish looked like a millstone.

Also, the English name is “sun fish”, which means “sun fish”. In fact, many countries, such as Indonesia and Russia, also derive their names from the sun or moon.

Why do these origins have so much in common? The origin of similar names is related to the mysterious characteristics of sunfish.


Is it true that sunfish lie down and take a nap?

Sunfish is a fish with many mysteries, and there are ecologies that have not been clarified. Its particularly mysterious feature is its appearance of lying on the surface of the water with its body sideways.

People who go out to sea like fishermen often witness this behavior, but the meaning of this behavior is not clear. There are theories that this appearance, which looks like taking a nap, is to have water birds eat parasites or to rest the body.

This behavior is so characteristic and impressive that people all over the world have likened sunfish’s behavior to the sun or moon.


Why do sunfish live there?

Sunfish are fish that live in the open ocean, so their detailed ecology is still unknown. Studies with transmitters have shown that they move back and forth between the deep sea and the surface, but because of the wide variation between individuals, their true intentions are still unknown.

It is hypothesized that this is due to the influence of water temperature. It is very exciting to see how research will progress in the future.

What do sunfish eat?

Sunfish are said to feed on jellyfish and plankton.

Jellyfish are not creatures that swim vigorously in the sea, but rather float gently. Sunfish are not good at swimming either, so it is said that they have learned to eat jellyfish, which are easy to prey on.

However, when examining the contents of their stomachs, shrimp, sardines, and squid have also been found. Some species live in the deep sea and are thought to dive into the deep sea to feed.

How do sunfish swim?

Sunfish are not good at swimming. They have a very different morphology from other fish, so you can imagine what they look like. Let me explain what is different about them.

When you think of sunfish, you probably think of the two large fins that develop up and down. These are the dorsal and anal fins, and they do not have the ventral and caudal fins that other fish have. So how do they swim with fewer types of fins than other fish?

First, propulsion forward is obtained by moving the dorsal and anal fins in the same direction. It’s like a bird flapping its wings.

When turning left or right, they use the rear end called the rudder fin or bridge tail. By the way, the rudder fin or end tail is called a fin, but it is actually a modification of the dorsal and anal fins.

Because their bodies are large, their swimming style is elegant and relaxed.


How fast does a sunfish swim?

Sunfish are generally thought of as being slow swimmers and not very good at swimming. However, they don’t always swim at full speed.

Sometimes they swim against ocean currents. The average speed is about 2.0 km/h (1.2 mph), and the maximum speed is about 8.0 km/h (5.0 mph)1.

When they catch food or feel threatened, you can see sunfish swimming “seriously”.


Is it true that sunfish die quickly?

The so-called sunfish weakest legend that became popular on SNS for a while. It seems that the rumor was spread as “interesting” content, and as a result, it led to more rumors.

Representative examples include “dies from the impact when jumping from the sea surface and landing” and “gets burned and dies when exposed to sunlight.”

However, it has been denied many times by aquarium staff and researchers. Sunfish is not a fish that is easy to die.

However, it is true that it can hit the glass of the tank without noticing it or leave marks just by touching it with your hand.

It is not easy to die, but it is true that it is a delicate fish.


Is it true that sunfish lay a tremendous number of eggs?

Along with the sunfish weakest legend, there was a story that was spread that they lay a large number of eggs at once. The number is as many as 300 million.

Moreover, it is said that only a few can survive out of them, and it has become famous as an episode of sunfish. However, this has also been denied by researchers.

Regarding the 300 million eggs, it seems that past papers were the basis. The paper only described “discovering more than 300 million immature eggs in the ovary.” It is difficult to imagine laying all of them at once from the development status of the eggs, and it is now considered that they lay eggs multiple times.

Furthermore, since there is no evidence or method regarding the 300 million eggs in the paper, it seems that it is not clear whether there are actually 300 million or not.


Can you eat sunfish?

Sunfish is not considered edible nationwide, but sunfish dishes are served in some areas. Actually, sunfish, which is considered delicious, is difficult to distribute because it is prone to deterioration.

On the other hand, fishing is thriving in Taiwan, and many restaurants offer sunfish dishes for tourists. Since there are not many opportunities to eat sunfish in general, if you visit a restaurant that offers sunfish dishes, you may want to try it.




Type of sunfish.

  • Sunfish.
  • Bump-head sunfish.
  • Hoodwinker ocean sunfish.