Hi all, I joined this forum in hopes of getting help with with a doxycycline dose. I have a vet appointment Saturday for my two new weaned rats who have been constantly sneezing and sounding mucousy (appears to still be in sinuses). They appear worse overnight, still eat etc, but I want to make sure they make it to the vet appointment Saturday am. I haven't owned rats in about 6 years and I guess tetracycline is no longer available in my state (though I do have a friend who has leftover oxytetracycline). I also have tylan 200 but it's injectable only. Anywho, I have this doxycycline for fish. It's 250 mg in each packet. Does anyone know how much of this I would have to use for a 42.7 gram rat and a 57 gram rat and how should I administer this?