Marusei Koi Farm is one of the largest koi farms in the Niigata region. Originally founded by Seitaro Hirasawa, the farm is now run by his son Yoshiyuki. They have become well known their varieties of koi such as Go-Sanke, Kujaku, Hi-Utsuri, Chagoi, Shusui, Benigoi, Mizuho Ogon, Asagi, Aka Matsuba, Yamabuki, Karashigoi, Kinmatsuba and others.
