Mouse escaped, scared; does she need a friend?

Question

Ruby in her cage right   So, about 6 months ago(or somewhere around that time), I got two young female mice named Christina and Ruby from someone who could not take care of them. Around two months after I got them, Christina died and Ruby ran away. I assumed that Christina had been sick because she had been acting weird for a while before then and that Ruby had also been sick and died after running away. Apparently, I was wrong. Two weeks ago, I saw my cat chasing something around my room. After searching for two days, I discovered that it was Ruby. I caught her in a box and now have her in a small plastic cage(Kritter Keeper). I am planning on getting a tank for her that she cannot escape from. For a while she seemed to have a hurt leg because my cat had caught her once, but now it seems fine and she is running on her wheel fine.
I have a few questions though:
Since I have ten gerbils and one hamster right now, all I have for food is hamster/gerbil food and some lab blocks. Is this okay for her to eat or should I get her some mouse food? I also give her some bread with a tiny bit of peanut butter as a treat sometimes(that is okay, right?).
Also, she seems kind of lonely and bored, should I get her a mouse friend?
And she is not friendly is there a way I can get her to let me hold her and pet her? Or is it a lost cause since she is like a wild mouse now?
Sorry about the cluelessness. I am used to taking care of hamsters, gerbils, and ferrets. Many people give my mother them if they can not take care of them and I take care of them. That was the only time that someone gave us mice.
Thanks in advance. :)

Answer
Dear Mandi,

Ruby is a pretty girl. I am glad you were able to rescue her and Christina.

Yes, she needs a friend. Mice are very social creatures, unlike hamsters, and female mice should never live alone (males fight). If possible there should always be three females together, so that when one dies there is not a mouse who is not only sad and depressed  to have lost a friend, but also lonely. A single mouse, lonely mouse, or sad mouse can be at risk for getting sick as well as for mites. The two mice in my sleeve right now agree, as they lost a companion last night and they are glad they have each other.

Unfortunately, a mouse who has been on the loose can have a drastic personality change from the trauma. Being chased by the cat didn't help either, poor thing. You will need to treat her as a new, timid mouse. You have a lot of pets and so you probably don't have hours to sit at a time to tame her, but a little bit preferably twice a day should help. You can decide if you want to give her boring rat and mouse blocks pellets for the moment so she is more interested in your treats. To the food question, she should have food formulated for rats and mice, whether a seed mix or blocks/pellets; never something formulated for another animal, though if you use hamster food for a little while till you can get  mouse food, it is not going to hurt her in the short run.

The basic idea is to put your hand in the cage for 15 minutes at a time for her to get used to it, and then slowly get her interested in a treat on your hand, which you slowly (over time) move from your fingertips to the palm so she has to climb on you. When she climbs on you you can lift up your hand just a tiny bit and put it back down, until she is used to being picked up. In the meantime, if she is handleable at all, if you take her out in a toilet paper roll, you can hold her in your closed hand or in the bottom of your shirt rolled up to cover her, so she feels safe and is smelling you.

It is commendable that you figured out she had allergies to her litter. The two usual litters are either a Carefresh type paper litter (not dyed or bleached) or aspen wood chips. If you have tried both those of course don't try again. There are also litters made of corn cobs, wheat, or alfalfa hay.

Last note: the peanut butter should either be mixed with water or be spread extremely thin, because choking is a real hazard.

Ruby has a dedicated and loving human companion, which is wonderful considering what she has been through.

Best of luck to her. Let me know how the taming goes.

squeaks,

Natasha