i used to breed bettas too
Half moon and crowntail mainly
my ultimate goal was OPAQUE HALF MOON BETTAS but i never got around to trying it
http://vanriel.myadsl.nl/Colorgenetics-OpaqueHM.jpg
even then this isnt a real 100% opaque it has a pink body and not the opaque color....hard to do because the red wash will most likely be in there in the genetics but can be bred out :P but thats another forum and topic :P
on the site it talks about color genetics if anyone in here wants to start and breed by genetics and not go at it all un uneducated
here.... The genetic make up of a opaque white is represented by: C bl Si Nr Op
C - The cambodian gene for lack of dark body pigment which causes the light body.
bl - Steel blue pigment which appears silvery-white when on a light background.
Si - The spread of the iridocyte pigment, in this case steel blue over the fish.
Nr - Non-red, causes the inability to produce red pigment.
Op - Opaque, the special gene that cause the powdery appearence of the fish.