Hi guys.
Apparently I didn't quarantine well enough... and the sniffles that my new rats had (which I am still treating with duramycin) were caught by my existing colony. I actually lost one of my adult males (close to 1.5 years)... But he has a history of respiratory issues, so that wasn't shocking. That said, he went from visible symptoms, and being treated to being dead in about 3 days time. The other adults seem fine at this point, but everyone is on duramycin (tetracycline water-soluble).

Unfortunately, I've noticed the young girls (my new rats) have started sneezing and slightly clicking (when breathing) again... And this is while being treated. So, I thought I'd post and ask you guys what you would suggest I treat them with.

My current options are:
Up the dosage of duramycin (I'm doing 1/2tsp. in 8oz of water now and should continue treatment through next Tuesday).

Amoxicillin (I had already purchased the aquarium variety, 250mg. capsules but I can't remember the dosage).

Baytril (this kind for birds that is in liquid form). I've heard this isn't good for young rats though and have no idea on dosage

Or, if you know of something else I could use that would be available at, say, TSC, that would be great. I already took all 6 of the new rats (2m/4f) the vet last week due to odd scratching and scabbing on some and spent a lot of money, so I'm hoping to treat them without going back in... I am also treating them with ivermectin, btw. in case there are drug interactions.

Thanks for your input!