I got a betta from Petco about 2 weeks ago to start up my sorority, labeled as a veiltail female. I noticed she had pretty large fins but didn't really think anything of it. She was easily the most aggressive girl in the tank (she was only in there for a day or so) and I removed her. Now I'm starting to question if she's a he.
I'm almost positive that she has an ovipositor, its hard to see past her pelvic fins and she never holds still long enough. Or could just be a light patch of scales. She gets stripey very easily.
On the other hand, she had a mini-bubblenest going on about the size of a quarter, and while she was with the other girls she relentlessly chased everyone around, full flare, has an impressive 'beard.' And her fins are massive in proportion to her body.
I'm so very very very confused >.< I managed to get a few pictures with my phone while I changed her water but she's very wiggly. I call her Franky.

^ p.s. No that's not her home, that's my plant QT lol