Okay so a few weeks ago I had 10 month old guppies, 5 females and one male... I come clean the tank and I notice one of the females is developing a lot more color. I think hmmm that's odd. A few days later she has completely lost her gravid spot and now has a gonopodium, I have been keeping guppies for a few years and never had that happen. He appears to be sterile and never chased the girls around