breathing trouble - no other symptoms

Question
I have a rat (Zelda) that is just under a year and today she is having trouble breathing. She looks otherwise normal -- no purple feet, no discharge from eyes or ears. I know she doesn't normally breathe that rapidly though. Any chance this isn't lung cancer? I just lost a rat to what looked like pneumonia. It took less than 24 hours for her to go from fine to dead. I had just started treating her with an antibiotic but it was unsuccessful. I'm worried that Zelda may be showing the first signs of what Victoria died of and that I just missed that Victoria's breathing changed before she showed obvious signs. Thanks for your help.

Answer
What your other rat had sounds like strep pneumonia (no relation to strep throat)  It starts out of the blue and kills within 12 to 24 hours.  Sometimes the pneumonia is resistant to many antibiotics if its not strep pneumonia and there is nothing that can be done. Its more viral. Not all rats catch it unless they have a weak immune system.

I would get your rat to the vet. Sometimes rapid breathing is the only outward sign we can see but the vet may hear something else.