No. Everything is plastic. To be honest, I don't do any rearranging or "introducing." I just let the girl loose.

And I've had no problems at all with this method. But I also think I have an extremely mellow sorority. I don't even know if I have an alpha female. If I do, I can't identify her.
I'd like an NPT sorority but my mother has claimed this tank and won't let me change anything. o.O