Koi can come in a variety of bright and attractive colors. The most popular one is the black koi. The Japanese honed and developed the skills needed to breed this type of fish. They studied its habits, breeding patterns, and diet.Although there are many of colorful koi out there, the most popular one is the black koi. With its black base coloring, this remains to be the cornerstone of the species that evolved from the Chinese carp. Unlike what its name suggests, most of the varieties of black koi have their own color variations as well. Here are a few of the following:
- The Karasu, or crow. This is known to be the oldest known black koi. Although they appear to be entirely black when seen from above the water, the underbelly can actually be white or orange. They just appear black because of their purely black upper body and fins.



