Animal Observation: Rose is very sick.

My two rats have very different personalities and on any given day I've come to expect certain "typical behaviors" from each.  Usually this starts when I open up the cage door and am immediately greeted by an eager and friendly Penelope.  She'll crawl up my arm and onto my shoulder before the door is done being opened.  

Rose, however, is a bit more skittish.  She'll come up to investigate me and then immediately dart around the cage for a while before deciding to come out.  Her trust in me has grown a lot, however, and she'll join Penelope on my shoulder in a matter of moments.

Today, however, Rose has been quite different.  When I opened the cage door she didn't move at all.  Upon closer observation I noticed that she was breathing, but extremely groggy and slow.  Once she noticed me she came to the door and crawled onto my arm, but she didn't have the strength to climb any further.  I held her for almost an hour hoping that she was just tired and would soon be her normal hyper self, but her condition didn't approve.

I called my boyfriend and told him that I thought Rose was dying.  He left work and immediately took us to the animal hospital.  They said that she was severely dehydrated and thin.  Penelope is completely healthy, however, so she guessed that it could be some type of virus.  We have been given instructions to give her liquids using a feeding syringe and to try feeding her mushed pellets later this evening.  She described her condition as "critical," but said that she should go home with us anyway because it'd be better for her.

Right now Rose is sleeping on a warm water bottle and wrapped up in an old shirt of mine.  She still isn't moving, but all I can do right now is hope for the best.

Here are my girls.  Rose is in the front:

Edit: Rose has passed away. It happened about 10 minutes ago. It's hard to lose a pet. Especially so suddenly.