I was wondering if you could give me some tips on what characteristics I could look for while shopping for a pet rat. I own mice right now and am content with them, but I would like an animal a little larger that can be kept in a cage. The best thing to do in choosing a healthy pet rat is to take your time and check out the best possible sources. Generally speaking, I think that the best place to start looking for a pet rat is through local rat clubs. If there is a rat show in your area, this is a great place to find local breeders with available babies, and oftentimes, rescues who are in need of good homes.
Many pet owners purchase their pet rats at the local pet shop as well.
You need to be very careful as there are good and bad pet shops. Many don't take care to provide disease free stock and you can end up with a pet that is not in the best physical condition that requires constant vet visits. One that has been handled and socialized and used to interacting with humans from birth. They should show interest in you and not shy away from your touch or nip. Eyes should be bright and alert.