Shimabara Spring Water Swimming Carp Streets

Shimabara City's residential streets flow with crystal-clear spring water emerging from underground volcanic aquifers below Mt. Unzen. The traditional water channels (shimabara no yusui) run alongside roads through the old samurai district, and residents have historically used these channels for drinking water, rice washing, and cooling vegetables. In the 1980s, the city introduced colored carp (nishikigoi) into the channels, creating the surreal sight of ornamental fish swimming through residential streets.

The main channel (Shimeisou Water Path) is 100m long with 1,500 carp in turquoise water flowing at walking speed. The water is 15°C year-round and emerges at 4,000 tons per day from the central spring source.