Between males and females it doesn't matter each betta has their own personality but females are little pigs and love to eat so they seem to like to say 'hi' more so they can beg for food, lol.

My female, Neptune, had really long fins for a female but she was definatly girl, even longer then your white girls finnage. Your white girl looks to slim to be male she looks really feminin I guess hehe. Blowing any nests for you? Thats another sign, hehe.

Oh and I love the tanks! Do you have a black background on it? It looks nice. And congrats on the girlies!