Merfolk, Mercreatures, Mermen or Merpeople are legendary water-dwelling, human-like beings. They are attested in folklore and mythology throughout the ages in various parts of the world. Merfolk, Merpeople, or simply Mer refers to humanoid creatures that live in deep waters like Mermaids, Sirens, Cecaelia etc.
In English, female merfolk are called mermaids, although in a strict sense, mermaids are confined to beings who are half-woman and half-fish in appearance; male merfolk are called mermen. Depending on the story, they can be described as either ugly or beautiful.
Chinese rényú () stands for "merfolk", but in ancient geographical or natural historical tracts, the term referred to "human-fish" or "man-fish" purported to inhabit rivers or lakes in certain parts of China. The Japanese analogue ningyo () likewise translates to "human-fish" while, at the same time, having also applied to various human-like fish recorded in writings from medieval times into the Edo Period.
China
Certain fantastical types of "fish", generically referred to as renyu (, "human-fish") are alleged to occur in various parts of China according to the Shan Hai Jing (Classic of Mountains and Seas, 4th century BC). It is mentioned in the Bei Shan Jing ("Classic of the Northern mountains"), Zhong Shan Jing (Central Mountains), and Xi Shan Jing (Western Mountains) sections of this work.
Another tale from Guangzhou tells of a merchant who, upon reaching an island, was captured by two women and taken into the mountains. They fed him daily, but he couldn't tell if he was still alive. After about a year, he overheard the women discussing magic, and he begged them to take him to the place where it was performed. When they did, he sought help, causing the women to flee by flying away. Though he was revived, his food gradually dwindled, and he died two months later. (translated as "resemble catfish")