Nothing too crazy:Hah. Ya I know the feeling, have had that happen
What qt procedure are you doing?
I have a 40 breeder & a 20 gallon QT with show tank water in it rolling all the time.
Fish stay in there for observation for a few weeks to get them eating and used to my water.
If I see something then I treat for whatever it is, mainly copper power, chloroquine phosphate and prozipro. (I follow directions on the bottle)
Once full treatment is finished I observe for a week or two then add them to a holding tank for more observation that is connected to the system.
Once they are eating well and used to the system water I add them to the show at night and wish them the best of luck.
There are better and more detailed QT processes but that is what works for me.