My rat is losing weight

Question
Hi. I own two female rats that I have had for about a year. One of the females seems to be losing weight continuously and I have no idea why. Her sides are starting to go in and she isn't as active as she used to be. I got her from a pet store. I feed them rat food that I get from the pet store and I also give them fruit, veggies, and little bits of meat and cheese. I have no idea why she is losing weight so if you have any idea it would be great!

Thanks,
Amanda

Answer
Well; she's probably sick, it may be something related to mycoplasmosis but it could be something more serious like cancer. Honestly, the best diagnosis will come from your vet. In the meantime, keep her interested in food by offering her pedialyte, carnation instant breakfast, puddings and baby food -- soft, easy to eat things - and lots of clean, fresh water.