Sudden rattie death

Question
I was heartbroken to find my little Louie this morning dead in his cage.  I am trying to find out what might have happened to him.  The basic facts are:  male intact rat, young cagemate x 3 months (they got along great!  Yes they had their spats with the youngster tried to get out of line), upper resp infection about a month ago treated with Baytril; completely resolved as far as I could determine; yesterday he was fine; I noticed a little weight loss but he sat on my shoulder while I typed on the computer and ran about on the desk being the same little pesky guy that he always was.  This morning he was on the bottom of his cage, teeth latched onto the cage wire; blood coming from his nose.  I am aware of the reddish discharge that rats can have; but this was BLOOD, believe me no question about it.  Julio (his cagemate) had blood on his fur and tail but then I also noticed that the tissue box they slept in together was covered with spewed blood; blood was also noted on the side of the water dish.  Any idea what could have happened to my little guy?  Life will never be the same - Louie was the coolest.....

Also, Julio is only about 3 months old - please make recommendations on getting another rattie....

Answer
Louie may have had heart and lung failure, or perhaps just one or the other.. but both can be common in rats with a history of respiratory problems and heart failure is surprisingly common in rats, especially males. I'm very sorry for your loss.

Julio is young enough that he should be fine to go in with any youngster his age or younger, and I would highly recommend going through proper quarantine when you bring a new rat in. You can never be too careful!