She should have been culled early on if it is a defect, which makes it a huge mystery. Maybe her tail will grow back, it could just be an injury. Only time will tell. But she'll be fine either way, and I don't intend to breed her ever. She will simply be a pampered fishy for the rest of her days.
And she's lucky, cause my favorite pet store is moving and everything is on sale so they don't have to move as much stock. I'm going out there this weekend to pick up some supplies. I love this place, when I got my fish, Bettabettabetta, from them, the woman said "Bye baby, I'll miss you" to the fish... It was sooo cute! It's one of those little pet stores where the few employees they have really care about animals.