May 13, 2013 · Email 2. People often ask me what kind of small-scale fish farming they can do in a backyard and still make some money. Well, ornamental fish may well be the answer. The ornamental fish trade covers cold-water pond fish such as goldfish and koi carp, as well as the hundreds of species of tropical fish traditionally kept in heated indoor aquariums. South Africa imports several hundred boxes of ornamental fish each month, mostly from Singapore, Taiwan, and Malaysia, but also increasingly from