When a butterfly koi and a regular koi mate, the resulting offspring may exhibit a combination of the butterfly koi's elongated tail fins and the regular koi's shorter, more traditional fins. The body patterns and coloration of the offspring can also vary, showcasing a blend of the distinct markings and colors of both parent koi.
Generally, the offspring from a butterfly koi and a regular koi mating will have intermediate traits, falling somewhere between the extreme features of their parents. However, there can still be significant variation among the offspring, with some individuals more closely resembling one parent or the other.
While butterfly koi and regular koi can interbreed, it's important to note that controlled breeding practices are often used by koi enthusiasts to maintain specific traits and characteristics within their koi populations. By selectively breeding koi with desired features, breeders can preserve and enhance the unique qualities of different koi varieties.