The clear fin trait is sometimes called "cellophane."
I'll be curious to see if this one is a marble or just a butterfly? If the pattern changes over time, then you'll know it's a marble. Otherwise, the base being one color and the fins another makes it a "butterfly."
It probably also has some Cambodian blood- that's where the flat red body color is coming from.
He is a pet store betta. More white when I purchased him. His body has grown darker. He blows bubble nests at least once a week. He is probably one year old+. So I don't think his color will continue to change