West Lake Fish in Vinegar Gravy (Chinese: 西湖醋鱼; pinyin: xīhúcùyú), also known as Song Sao Fish (Chinese: 宋嫂鱼; pinyin: sòngsǎoyú), is a traditional local specialty dish of Hangzhou in Zhejiang. It first originated in Southern Song dynasty. The material of West Lake Fish in Vinegar Gravy usually is the grass carp. After cooking, the chef will pour the smooth sugar and vinegar on the fish, which will cause the pectoral fin to stand up. In this way, the fish is tender and sweet with special crab flavor.