Mola sunfish is a large oceanic fish, with a maximum body length of 3.0 to 5.5 m and a weight of 1400 to 3500 kg. They swim alone or in pairs, sometimes in groups of more than ten. Small individual fish are more lively and often jump out of the water. Large individual fish move slowly, often lying on their sides on the water surface, or their dorsal fins are exposed out of the water. They can also dive into water more than a hundred meters deep. Feeds on seaweed, molluscs, jellyfish, planktonic crustaceans and small fish. The number of eggs it carries is extremely large, up to 300 million, which is the largest number of eggs among fish. Juvenile fish are covered with tumor-like spinous processes, which gradually disappear with age, and the body becomes oval.

Sunfish is a mid-ocean and surface fish. It migrates to the shore with the Kuroshio. It is carnivorous, mainly eating jellyfish and zooplankton. It also eats crustaceans, jellyfish, and seaweed. Sunfish swims at the fastest speed. Slowly, when the weather is good, it will expose its dorsal fin to the water and float with the water, basking in the sun to increase its body temperature; when the weather gets bad, it will flatten its body and float flat on the water, using its dorsal and anal fins to paddle and control the direction. , and can also use its dorsal fin to somersault in the sea and dive to the bottom of the sea.

The sunfish has a docile temperament. It lives in tropical oceans and is often surrounded by many luminous animals. When it swims, the luminous animals on its body will emit bright light, which looks like a bright moon from a distance. Therefore, It is also known as the "moon fish". The top-heavy body of the sunfish is very suitable for diving. It often dives into the deep sea to catch deep-sea fish and shrimps for food. Living on the surface of the ocean, they can dive to depths below 600 meters, sometimes as many as twenty times a day.