The Marudo Koi Farm is a renowned Koi farm located in Nagaoka, Niigata. The farm is currently run by Hirasawa Hisashi. They are known for their unique combination of Koi varieties including Go Sanke, Asagi, Hikarimono, and other varieties.

The farm is known all over the world and is constantly expanding its range. Especially, their Sanke and Kohaku are highly valued for their strong colors and perfect physique. They also grow Showa, Asagi/Shusui and Ogons to a lesser extent.

The farm has a large raising area of 100,000 m. They offer a great selection of Koi.