In Japanese folklore, the giant catfish believed to cause earthquakes by thrashing its tail is Namazu.
The legend places Namazu beneath or inside the Japanese islands. The deity Takemikazuchi, associated with Kashima, restrains the catfish beneath a sacred foundation stone called the kaname-ishi. When the deity’s attention lapses, Namazu struggles and shakes the earth, providing a mythic explanation for Japan’s frequent earthquakes.
The association between catfish and earthquakes developed gradually. It was known in parts of Japan by the 16th century, but became especially prominent after the 1855 Ansei Edo earthquake. Artists produced namazu-e, woodblock prints showing the catfish being subdued, often by Takemikazuchi or the stone.
Namazu was not always portrayed only as a villain. Some 19th-century prints treated the creature as a force for social change because earthquakes disrupted wealthy hoards and created rebuilding work. Modern Japanese earthquake-warning imagery still sometimes uses the catfish as a familiar cultural symbol.