Rescue Mouse eating its Tail

Question
Hello,

I recently acquired an escaped feeder mouse that a snake owner no longer wanted. It had seizures i believe from the first day but quickly recovered with some TLC.

She was perfectly fine until i put her into the tank with my two other feeder pet mice whom are 8 months old and are in decent health. they were kept on pine bedding before i got them :( they sneeze. After the allotted 3 weeks of quarantine and some visits on neutral ground i decided they should be introduced and moved in together.

the first few days in the tank was fine but i noticed that the new mouse (Bandit) was missing a small portion of the tip of her tail, it was white and to the bone but not bleeding so i removed her and assumed one of my mice attacked her because i could hear them squeaking the night before.

Back in hr own tank i continued to notice the tail being chewed and that in fact she herself was eating the end of her tail. shes lost probably around a centimeter of tail.

i am unable to bring her to the vet due to shortage of funds (my cat got surgery and had to eventually be put down :( )

Please help, i have no idea whats causing this, her tail has formed a pink oblong circle of no hair near the chewing and it bleeds occasionally. shes energetic, no labored breathing, her fur coats smooth and clear.

Thank you, thank you thank you!!

Answer
Hello Tannis,

Either the tail is bothering her, or she has  become a little bit mentally unwell, which is pretty common in mice.

Can you send me a photo of the tail? Was there any other behavior change at the same time?

I would try putting them back together, since she is doing the damage herself. They may even be able to distract her. However, watch carefully because her fixation with that part of her tail might be because she got a bite. But I don't think it could get worse; at least not from putting them back together. And mice are pretty sad living alone.

Are you on Facebook? It is actually easier right now to get my time there because I run a large rat and mouse group.

Squeaks,
Natasha