In the northern wastes there is a Lake Shi, a thousand li on each side. The banks are over five zhang high (one zhang is c. 3.3m), and it is permanently frozen, thawing only for forty or fifty days in summer. There lives the Henggong Fish, seven to eight chi in length (more than 2 metres), shaped like a carp and red. In daytime they stay in the water, but at night take human form. Stabbing will not pierce them, boiling will not kill them. Only a fire of two dark plum branches will finish them off. Eating them will halt illness caused by malign influence.
Li Fang 李昉, et al., Taiping guangji 太平廣記 (Extensive Gleanings from the Era of Great Harmony), 10 vols (Beijing: Zhonghua shuju, 1961), x, 464.3822: