Originally Posted by EvilVOG
It probably depends. I'm no expert on marbles but it seems to me there are different contributing traits and people call them all marble. The cause of the marble variant Koi is most likely Piebald, then there's the red loss gene, a possible true marble where individual scales are different colors, and even normal bettas that have an unusual coloring that someone just decided they would call marble to help their fish sell.
Not sure about that.
I don't work with reds and don't know much about red loss. Nor have I worked with piebald and koi genes thus know as much about them.
By marble, I'm referring to the "jumping" gene that makes bettas change color. Usually from dark color to what I call "no color" - pale/cellophane (sometimes dark to paper white or vise sersa) and sometimes change further either to it's original dark color or to a different dark color. I often get marbles from breeding non marbles - specially if I use new (bought betta) genes in my breeding. And further breeding their offspring will give me a few marbles..... partially dominant.