Recently one of the fish (a african brown knife) in my qt tank came down with a bad case of ick after treatment the spots went away how long until I can be certain it is gone and they are safe to move to my main tank?
Follow instructions of meds and do treatment for 14 days minimum. You have to do water changes to cope with clean water quality. At this point, dose again the med by the amount of water you replaced. I'd recommend doing 20-30% water change every 3 days.