Ooya Koi Farm, also known as Kataoka, is located in Koguriyama, Ojiya, Japan. The farm is run by Taro Kataoka. They specialize in breeding a variety of Koi, including Sanke, Kohaku, Showa, Asagi, Hikarimono, and Kawarimono.

The farm has a large raising area of 50,000 m. Taro Kataoka is one of the leading breeders in Japan. His Sanke has won many top awards at All Japan Nishikigoi Show.