After and earthquake in Edo, the Namazu went worshiped as a god. Namazu-e are a subtype of Umizo-e. It is believed the origin of the monster could be the fact catfish predict earthquakes.
The Namazu is now used as symbols for earthquake-related events, operation, and more. The Pokémon Whishcash is a reference to Namazu (more notable in Japan, where its name is Namazun). An episode of Pokémon was banned in Japan due to being aired after an earthquake because it contained the PoNamazu.