Cool colors.  A few have a black base with  blue/red or green/purple color shift spots.

Wild colors.  Some of these could be classified as “cool colors” too but they have green or blue that blends with other colors, so I classified them as “Wild”. There are a few oddballs with a black base and color shift, or metallic spots.

   

Koi colors. Most are natural looking colors but there are a couple with blue spots.