Rat Skin Problem

Question
I own two male rats. One of them is much more submissive and often bullied around by the other rat. From fighting, this rat sometimes has small patches of hair missing around his neck and base of tail and small cuts. Just recently, I noticed areas of skin on his back just above his tail that are a strange blue-grey color. Could this be normal skin coloration? Or is it related to the abuse he takes from the other rat? The patches of blue skin have fairly clean borders and are visible beneath areas where his fur is thinning. Or is it possibly some disease or mite infestation? Any info you have would be greatly appreciated. Thanks.

Answer
Some rats do what is called barbering. It sounds like your other rat is trimming the other rats fur as well. The blue skin color is not a good sign. You should take your rat to a vet as soon as possible. I can't really find anything on the internet about what causes the discoloration of skin, but they all suggest a visit to a vet as something is really wrong with the rat. I am sorry I could not give you all the answers, but I know your rat should see a vet asap.