My gf gave me an aquarium one month ago and she wanted to see some fry around. So, I got 3 black mollies (1M + 2F) and 3 guppies (1M + 2F). Fair enough!!
One month has passed, and no fry yet. Maybe it's too early, although females are still rejecting the males and don't look like pregnant.
Anyway, I have noticed days ago a very weird thing with one of our female black mollies: her fin is growing like a gonopodium!!
She is the biggest fish we have, and fat! For some time we even thought she was pregnant. So, by her size I would say at least that she is already adult.
First weeks she had a regular female fin. Then it started growing, getting thinner and longer. Nowadays she even move it around like males do.
Picture of my fat molly two weeks ago (after some zucchini, sorry
Picture of her today:
Picture of her moving her fin around:
I'm skeptic that "she is male" because I could have noticed when she arrived, but is it a normal behavior for a female?