Koi.co.za is a South African online retailer based in Valeriedene, Randburg, Gauteng, focused on koi, aquarium and aquatic-pet supplies. Its catalogue features a broad selection of fish foods and specialist diets, including Hikari products for koi, tropical fish, goldfish, bettas, cichlids, discus and marine species. Shoppers can find options for different feeding needs and life stages, such as growth, colour enhancement, sinking foods, staple diets, pellets, wafers, sticks and first-food products. The range also includes foods for turtles and other specialist aquatic animals, as well as filtration products and pumps, including BioCentric items and the gULP Base Unit.

Customers can browse and order through the website, where products are listed with prices and organised into categories. Koi.co.za says orders can be paid for by electronic funds transfer and are couriered to customers, with an indicated delivery timeframe of two to three days. The site also invites visitors to subscribe to its newsletter for news and special offers, and states a customer-focused guarantee: if customers are not happy, the retailer is not happy.