Sole is a family of plaice, with about 103 species in 3 genera, about 32 species are known in China. The tongue sole is flat on the side and long tongue-shaped. The eye is usually on the left side of the head, and the tail-hyoid bone is longitudinally narrow and plate-shaped. The intermedullary spines, the odd fins are completely connected, without pectoral fins, one pelvic fin is connected to the anal fin, the genital process is often connected to the left side of the anal fin, the renal vein spines are short and horizontal, and the eggs have 50 to 100 small oil balls. Mainly tropical bottom sea fish.