Mouse behaviour. Are they sick?

Question
Hello, so I have two fancy mice as pets and they are both about 16 months old ish. My black one, Muschi, is just getting over pneumonia and she has been getting antibiotics, and fancy wet food to suppliment her diet because she was very thin and not eating. She also has a scratched cornea, and I have been putting some ointment on it and she is getting better.
        But the other mouse I have was not sick. But I have noticed something that is freaking me out a ton. So tonight I was just playing with them and holding them and whatnot, and haifisch all of a sudden got super agitated and then bit me, and then kind of went limp when I put her back in the cage. Her legs didn't seem to work, and she wasnt walking or moving around. I could see her breathing and her eyes were open, so I don't know. I then poked her, and she started moving and then ran down the little tube they have but she didn't want to come out the other end. Her little cute head was poking out the opening and I just kind of poked her on the top of the head to see if she was ok, and she FREAKED OUT. She started strashing around and it scared me so I took my hand out of the cage. She landed in a spot after she was done going crazy, and she has just been sitting there ever since. it has been like 10 minutes and she hasnt moved. She is still alive, but I am to scared to touch her because I don't want to get bit or to hurt her.

What is happening? I am so confused and really worried. please help ASAP.

Answer
Dear Erin,

If she is still agitated in 24 hours then it is probably a brain tumor (pituitary tumor) or brain damage (from a stroke), and she may need to be put down.

If she gets better, it may have been some kind of a seizure, which could happen again. Or it could be damage from a stroke which healed. It is also somewhat possible but doubtful, that she had an emotional reaction to something; but there was so much freaky behavior that it is hard to imagine it.

In any case, the most important thing is whether she is happy. You will be able to tell. Every day you ask yourself (or her) if today is a day she is glad to be alive. It is a hard decision for anyone.

Now is also the time to get some new mice, so the other mouse is not alone when her friend goes. I always recommend triplets of mice so when one dies there is time to replace it without there being a remaining mouse who is not only bereft but also lonely. The only time this is not appropriate is if you are phasing out of mice; in which case the last lone mouse needs a lot of love.

I hope Haifisch is OK. Haifisch and Muschi, Hm. Shark and kitty. Is it the sharp little teeth?

Squeaks,

Natasha