It is clear that the Japanese took a lot of pride in selectively breeding koi fish to produce the different gorgeous color patterns we see today. Their spectacular colors and patterns are part of the reason that koi fish are still loved today and are treasured by their owners.

The colors of a koi fish should be bright. A red koi should be bright red and a black koi should be deep black. A dull black or a fish containing scales or spots that are slightly graying does not reflect well on the fish. As would a white koi that is not pure white as snow but contains specks of dirty grey. Color is an indicator of good health.

With koi, if they are in poor health or are exposed to poor water conditions, they will change color. Their bright colors will turn dull. If you are looking to buy koi fish understanding how a koi's color is supposed to look can help you in picking out a health fish. In turn, while caring for koi of your own, keeping a close watch on the color of your koi will determine if you are giving them the best care possible.

Koi fish come in many different colors. Some of the major and most seen colors are red, white, black, yellow, blue and cream. The Japanese used certain terms to describe the colors and traits of koi fish. Koi fish breeders have identified and named a large number of specific categories.

The most popular category is the Gosanke category which includes Kohaku, Taisho Sanshoki and Showa Sanshoki varieties of koi. The Kohaku koi variety are white with red markings. The white coloring on this breed of koi should be pure snowy white and the red should have well defined edges that cover between 50 and 70 percent of the body.

The Taisho Sanshoki variety of koi which is also known as Taisho Sanke or just Sanke, are white fish with red and black markings. Like most white coloring on koi, the white coloring should be pure snowy white while the red and black colors are deep in hue with distinct edges. Similar to the Sanke variety of koi, the Showa Sanshoki, or just Showa variety of koi are also white, black and red in color.

The difference between the two is that the Showa koi is predominantly black with red and white markings. Other koi varieties all have their own color markings. For instance the Ogon koi breeds come in a variety of colors but are all one color. They should be an even hue all over their body with no patterns or markings.

It is possible to enhance their koi's colors by feeding them a rich diet. Shrimp, marigold, plankton and blue-green algae known as Spirulina are examples of types of food that have been added to commercially prepared foods specifically geared to enhance the color in koi fish. Plus, feeding koi frozen or freeze-dried foods like brine shrimp and daphnia, you are ultimately feeding them color-enhancing ingredients. Each of these types of foods have high concentrations of carotenoid pigments. Carotenoid pigments are the major pigments of the koi's skin.