Flounder, also known as flounder, lives on the sandy bottom of shallow sea and preys 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. The "iron chest" commonly used in Chaoshan area to wrap jiaozi is actually a dry sole, which is made by drying the sole.