Introduction about Koi fish
Koi or Fancy carp are decorative types of domesticated common carp (Cyprinus carpio) that are retained for ornamental purposes in outdoor koi ponds or water gardens. Koi types are usually identified through color, patterning, and also scalation. Many of the major colors are white, black, red, yellow, blue, and cream. The most famous type of koi will be the Gosanke, which is composed of the Kohaku, Taisho Sanshoku, and Showa Sanshoku varieties.
Cyprinus carpio or typical carp is a species of fish from the family Cyprinidae. The beginnings of the common carp trace to the Caspian Sea, in which the fish naturally moved to the Black and Aral Seas, east to eastern mainland Asia and west so far as the Danube River. From the same family, the Prussian carp (Carassius gibelio) were first bred for color strains in China over a 1000 years ago, where selective breeding of resulted in the creation of the goldfish. The very first recognized selective breeding causing ornamental fish.
Common carp were 1st bred for color in Japan within the 1820s, at first in the city of Ojiya in the Niigata prefecture on the northeastern coast of Honshu island. From the 20th century, numerous color patterns have been established, especially the red-and-white Kohaku. The rest of the world wasn’t aware of the development of color variations in koi before 1914 when the Niigata koi were exhibited in the annual exposition in Tokyo. At this point, the desire for koi exploded throughout Japan. The hobby of keeping koi eventually spread worldwide. (For the butterfly koi is one known product of such a cross)
Distinctions Koi fish from goldfish
Goldfish were created in China over a 1000 years ago by selectively breeding Prussian carp for color mutations. By the Song Dynasty (960 – 1279), yellow, orange, white and red-and-white colorations had been developed. Goldfish (Carassius auratus) and Prussian carp (Carassius gibelio) are now considered different species. Goldfish were introduced to Japan in the 16th century and to Europe in the 17th century. Koi, however, were developed from common carp in Japan within the 1820s. Koi are domesticated common carp (Cyprinus carpio) that are selected or culled for color; they aren’t a different species and will revert to the original coloration inside a few generations if permitted to breed freely.
Generally, goldfish are generally small compared to koi, and also have a greater variety of body shapes, and fin and tail configurations. Koi varieties generally have a common body shape but have a greater number of coloration and color patterns. They also have prominent barbels on the lip. Some goldfish varieties, like the common goldfish, comet goldfish, and shubunkin have body shapes and coloration that are similar to koi and can be difficult to tell apart from koi when immature. Since goldfish and koi were developed from different species of carp, even though they can interbreed, their offspring are sterile.
Thank you information from Wikipedia