The only betta species with a dorsal fin like that is a butterfly!
http://watershed3.tripod.com/types.html
tamtam said:I really don't think it's veil tail.. it has a rather rounded tail to be a veil.. I would say round-tail betta
http://www.aquaticcommunity.com/bettafish/tailfinforms.php
Out of species, coloration, and fin type, I am most interested in fin type.