Molidae is a family of fishes of the order Tetraodontiformes. The body is tall, short without a tail part and caudal fin. The dorsal and anal fins are high and short. The teeth on the jaws are fused in the form of plates. Includes 3 genera and 5 species. Marine, epipelagic fish of tropical, subtropical and part of temperate latitudes. Reach 3 meters in length and a mass of 1500 kg. Poor swimmers. They feed on squid, crustaceans, salps and others. Mola mola hatches more than 300 million pelagic eggs. Occurs occasionally in the Barents Sea, Sea of Japan, and off the Kuril Islands. Non-target species.

Fish belonging to the family Molidae have a very distinctive appearance. They have lost the tail and the back part of the spine, no spiny dorsal and pelvic fins, and the soft dorsal and anal fins oppose each other and shifted to the rear of the high, compressed from the sides of the body. Moonfish are common in the surface tropical and subtropical waters of the world's oceans, with some of the three species of this family reaching enormous sizes.

These fish have short, strongly compressed from the sides of the body, approaching the shape of a disk. The unusually thick and elastic skin is covered with small bony tubercles. Larvae and juveniles of this species swim as normal fish, and adults spend much of the time lying on their side, near the surface, lazily flicking their high dorsal and anal fins, alternately exposing them out of the water.

Molidae are very poor swimmers, unable to overcome strong currents. It feeds on zooplankton: crustaceans, small squid, eel larvae (leptocephalus) and a variety of salps, comb and jellyfish. It is possible that large individuals are capable of sinking to considerable depths.

Molidae - the most prolific fish: one female hatches up to 300 million eggs. The eggs are pelagic. Spawns in tropical waters of the Atlantic, Indian and Pacific Oceans, but adult fish, carried by warm currents, often penetrate and moderately warm waters. In the North Atlantic they reach Newfoundland, Iceland, Great Britain, the western part of the Baltic Sea and along the coast of Norway even to Murman. In Far Eastern waters, they are occasionally found in summer in the northern part of the Sea of Japan and in the area of the southern islands of the Great Kuril Ridge.