Don't want to get into detail but based on the long dorsal, the straight caudal edges and the fact that there's only 2 rays I'd say its a female delta with a doubletail geno.
Well since bettas are my thing, I'm going to ask a betta question, my apologies to those who don't paricularly like bettas.
What is the dominant color in betta breeding? Meaning which color is the easiest to breed into a line and the hardest to get out of a line if it's not wanted.
a. blue
b. chocolate
c. red
d. dragon
e. green
f. opaque
g. melano