Koi fish, or Nishikigoi, are the product of several centuries of breeding between the many different species of carp. The first color mutations appeared around 1805. Koi are available in all colors from the purest white, through yellow, orange, red, near lavender, blue, greens and coal black, in endless combinations. Most popular in Japan are Kohaku, a white fish with persimmon-red patches in a stepping stone pattern. In the USA, favorites run from the "Big Three" (Kohaku, Taisho Sanke, and Showa Sanke, the last two appreciated for varying proportions of white, black and red) to the eye catching Ogons, which are a metallic fish that look like they have been hammered from gold or platinum. Recent developments are the long fin or butterfly Koi and the Gin Rin Koi, where each scale sparkles like a diamond.
In Japan, koi are seen as a symbol of good fortune, luck, friendship, and love. Within the Buddhist religion they symbolize courage. Each of the different types of koi have their own symbolism based on color variations. Certain colors represent certain members of a family. For example, fish that are white and blue stand for a son in the family. Then you have the beautiful red and pink koi. The koi fish color meaning of the red and pink one is the daughter of the family. The vibrant flame red koi is symbolic of a mother within the family, and the father is represented by the black koi. The Ogons are symbolic of fullfillment in wealth, and success in business. Yamabuki is a gold color koi and stands for gold, wealth, and prosperity. Asagi koi happens to be the oldest type and coloring is a mix of gray and blue. Some of them come with a belly of red. These koi are one of the most colorful options and mean that your life and everything in it is going good.
Koi are omnivores and will eat a great variety of foods. Koi dispositions are mellow and their toothless mouths are soft. Once accustomed to your presence, koi will have no problem eating from your hands. They pose no danger to smaller fish. It is not unusual fro a a happy koi to live thirty years.