Short Fin (SF) Betta
All Bettas collected in the wild are Short Fin Bettas. Their normal finnage is short, somewhat like our domestic females, only a little more angular and pointed.
All of the other finnage types seen in Bettas are mutations of the original wild Betta, that directly affect their short fins.
Some of these mutant genes are inherited as simple dominants, while others appear to be sex influenced or cumulative multiple pairs.