Nice dithers, they definitely are a worth while addition. They do resemble Poecilia velifera, but hard to say, so many crossed bloodlines nowadays. Where did you get your sailfins, if you don't mind me asking?
Chicago guy brought them up to one of our clubs latest swap meets.
I counted fin rays, the velifera are known to have 18 or 19, latipinna 15 or less, I was only able to count 13.
Thats great. I wish I could do this with my grammodes. They have great colors but at 2" maybe tops they stay hid. Unless they're killing someone of course.