I concur, gorgeous. I had one Koi Betta for almost 2 years that passed away, I never could put my finger on what happened, it was so sad...RIP Joey.
He was bright red with quite a bit of white and some greenish cellophane accents on his tail when I first got him. As he matured most all of the white turned red and the parts that were red just got darker. He kept a hint of the cellophane, which was nice.
The one I have now, "Bunny
View attachment 100725" has followed a similar pattern, basically darkening up, but has retained more of the marble look, and a kept a
View attachment 100724bit more of a pinkish face. He may continue to deepen as he gets older.
He is quite a sturdy little guy, I just love him!
(I don't know the correct terms for coloring/markings).