KoKo/nKo
Koi is a marking that is spread on the body with textured patches. The only rule for Koi, is that the base color must be 30% visible.
The Patches color is not free to choose. The color must be close in "temperature", so the following color combination are permitted:
For the head markings every color is allowed regardless of the base color. Markings' color rules does not affect the head marking too.
Non-Dominant (nKo)
Recessive Koi allows you to add a “scale texture” on the patches!