Modern Koi carp are the result of a long and careful selection process. The first specimens of black carp appeared more than a thousand years ago. Subsequently, multicolored carp were also bred. Like other koi carp, Midori goi have a wide, thick body covered with large scales and a short, rounded head. They are distinguished by their uniform green coloration, which can range from a soft pale green to a deeper and brighter shade. The weight of an adult specimen can reach 40 kg.