About a week ago I got a pair of 5 week old rats, and one is dying. He was never quite as friendly as the other, but on day 3 he began to sleep more frequently and bite the shit out of me whenever I'd go near him. I figure I just needed to work with him some more. Today I went into their cage, a bit concerned as he had been more and more reclusive, and he's hardly able to move. His eyes are half closed, and hes barely moving his head. He's making effort to stay upright, though. He also has blood (I don't think it's mucus) covering one of his forelegs. The other rat is perfectly healthy.
Despite this, he still has interest in grooming and eating. He's having trouble though, so should I help by soaking the food? Cutting it into smaller pieces? It's Oxbow, I intended on switching it to a food better for younger rats later on.
Does anyone have any suggestions on what may be wrong? Or what to do, with food or otherwise? Thank you so much, I'm really panicking.