I've raised livebearers for years and I've heard of and seen swordtails change sex. I've never heard this same trait in Mollys. However, I have a Molly now that not only changed sex, but gradually changed color from a marble to fully black. When I first bought the fish, it was a female marble about 1 inch long. It looked to be a normal marble molly. I also had 2 other females mollies and 1 male molly among some other liverbearers. Now, the fish is definitely male, completely black, and a sailfin about 2 1/2 inches long. I've watched the gradual color change from black and silver to all black over several weeks. I've never heard of mollies changing like this and neither has my LFS. Has anybody else heard of this?