well i got her yesterday with another female from a pet store the owner housed the females and males together so she lived with like 20 males .No wheel,30 other mice,1 water bottle,1 food dish all in a 10 gallon fish tank she was cleaning herself i beleive and i looked over and she started banging her tail up and down now the 2 does live by themselfs (1 male by seperate),They have a food dish,wheel,treats,wooden chews,water bottle,time out of cage ,etc etc
Oh my...hun, I hate to be the one to tell you...but if she was housed with males...she and the other girl could very well be pregnant....
Secondly, it can take pet shop mice...mice that are not handled very well...up to two weeks to acclimate to their environment. She sounds unsure and afraid and upset. It will be up to you to tame her and make her trust you so that she doesn't feel the need to warn you off by rattling her tail at you. Right now,m she's afraid, not sure of her new home and stressed out. Give her some time. Rattling a tail means "I'm tough! I will hurt you! Go away! I'm warning you!".
Sounds like a for real mad mousie, and that makes sense considering how she was kept and all. Does can be very territorial and even get into fights with other does that are just as serious as the ones bucks might have. I have one doe who started chasing her cagemates (all does) and barbering, and when it escalated to biting I moved her to another smaller group tank where she was okay for a couple of months, then it started up again. Now she's housed with one very large doe (oinker) and is getting along fine. They have even built a lovely big nest in their mousie house. I suspect a mousie equivalent of social anxiety. She has a sister with the same sort of problem.