A friend gave me a few molly fry about a month ago. Say fry I'm not sure how only but were only just over 1cm long at the time they now about 2cm maybe little more. Noticed couple days ago one has a more round belly then the rest but it looks like I only have females from what I can see . Is she just a porker?
Here is a picture of a male. The females fin will look like a fan, the males well it condensed and looks like a well you know. I would feed a pea, and cut down on the feeding. They can die from over eating. called bloat.
Fish in Cycling