My koi pond is a pond of multi colored fish
Wow,  how does it look like? 
Very colorful, several varieties are recognized by the Japanese 
OK.  Have never heard of koi pond before,  tell me more about it
main colors are white, black, red, yellow blue
That looks colourful.  So do they separate the fishes in their colours
group of fish originally found in Central Europe and Asia. Various carp species were originally domesticated in East Asia, where they were used as food fish. Carp are coldwater fish, and their ability to survive and adapt to many climates and water conditions allowed the domesticated species to be propagated to many new locations, including Japan. Natural color mutations of these carp would have occurred across all populations. Carp were first bred for color mutations in China more than a thousand years ago, where selective breeding of the Prussian carp ("
Koi
Koi is an informal group of the colored variants of "C. carpio". Several varieties are recognized by the Japanese. Koi varieties are distinguished by coloration, patterning, and scalation. Some of the major colors are white, black, red, orange, yellow, blue, and cream. The most popular category of koi is the "Gosanke", which is made up of the "Kohaku", "Taisho Sanshoku", and "Showa Sanshoku" varieties.
History.
Carp are a large