Zebra Danio (Glofish) Lost Her Tail, Help?

[Kiminator]

I have a small castle in my 10 gallon tank, and noticed that one of my danios was stuck in one of the holes. When I removed her from it, she had worn off her tail and some side fins and is now sitting in the bottom of the tank. There are three other danios and one black molly with her, but they aren't bothering her. What should I do? Will her tail grow back?

 

[Sophie]

'worn off'?
How exactly?