Flatfish, also known as sole, is a general term for abalones. The body is very flat, rectangular, oval or long tongue-shaped, up to 5 meters long, and the adult fish body is asymmetrical from left to right. Both eyes are located on the left or right side of the head. The mouth is slightly prominent. Fins are generally spineless. The dorsal fin and the anal fin are longer at the base, and are connected or not connected with the caudal fin. Widely distributed in warm and hot seas of various oceans, it mainly feeds on benthic invertebrates and fish. There are more than 540 species in the world, including China 120 species. The main species are Siniperca chuatsi, Siniperca chuatsi, sole and sole, all of which are economic fish. Habitat in the sandy bottom of shallow sea, preying on small fish and shrimp. They are especially suitable for benthic organisms on the sea floor. Because their bodies are flat. Both eyes are on the upward side of the body, and the color of this side matches well with the surrounding environment; Their downward side is white. Flatfish has extremely fine scales on its body surface. The flounder has only one dorsal fin, extending almost from the head to the caudal fin. They mainly live in temperate waters and are important economic fish in temperate waters.