what's the difference between koi and regular goldfish
â¢ They both belong to one Family but two genera in the taxonomy. â¢ Koi is a developed form of the common carp, whereas goldfish is a selectively bred form of Prussian carp. â¢ Japanese bred the koi as an ornamental fish before 200 years, but Chinese bred the goldfish before 1,000 years.
Most of the differences between care for these fish are related to ponds versus aquariums. When goldfish are kept in ponds, or koi kept in large aquariums, these differences decrease. One big difference is that goldfish are small enough to bring inside for the winter if your pond is prone to freezing.