Adding fish after going through a fallow period

[Hilltopreef90]

I’ve waited several months after a disease killed all but one fish in my aquarium, I began by returning the one surviving fish after quarantining and treating him, 2 weeks later I bought another fish and after it’s quarantine period added him, he’s been in with the surviving fish a week now, when can I be fairly certain whatever originally killed everyone is gone and it’s safe to continue to quarantine and add new fish ? I’m other words how long after the second fish added would it take for it to die if the tank still had issues or if somehow my surviving fish was a carrier of whatever killed my fish initially?

 

[Fish Think Pink]

I’ve waited several months after a disease killed all but one fish in my aquarium, I began by returning the one surviving fish after quarantining and treating him, 2 weeks later I bought another fish and after it’s quarantine period added him, he’s been in with the surviving fish a week now, when can I be fairly certain whatever originally killed everyone is gone and it’s safe to continue to quarantine and add new fish ? I’m other words how long after the second fish added would it take for it to die if the tank still had issues or if somehow my surviving fish was a carrier of whatever killed my fish initially?

Not enough info on here to answer, but think you are okay. Also, healthy fish with strong immune system are more likely to survive XYZ. Continue to QT, observe, add slowly.

This is a recent guest speaker presentation that may help you feel a lot better about what you are doing. I doubt you have to worry about 'carrier' and given your QTing going forward you are improving your odds for success going forward.