Demi Koi is a koi-focused retailer based in Temple City, California, offering fish, food, publications, and educational media for koi enthusiasts. Its online shop features koi varieties including Showa and Kohaku, with individual fish listed for sale. Customers can also choose from several koi food products, including Tategoi, Taberu, and floating wheat germ formulas, available in small packages and larger bulk sizes. The store carries merchandise and publications, including the Nishikigoi Manual.

Beyond its products, Demi Koi shares practical information through articles, videos, news, and frequently asked questions. Its video content includes guidance on distinguishing Sanke from Showa, catching koi, and recognizing red-and-white varieties. The business welcomes visitors at its Temple City location on Saturdays, Sundays, and Mondays from 11 a.m. to 5 p.m.; visits at other times can be arranged by appointment. Customers can contact Demi Koi by phone or email for questions and visit planning. The brand presents a mix of koi sales, care-related supplies, and learning resources for hobbyists.