I must be paranoid, i quar for 4 weeks. Sometimes fish take a little longer to show signs of illness, plus you don't know what they have been in contact with before you got them. Some fish can live with different diseases they have been in contact with, having built up a sort of immunity, while still being carriers. More sensitive fish are prone to this,such as discus & altum angels.
Wild caught fish can live with things & be carriers, many discus breeders who get new fish in will take a couple of their larger, not so great looking fry, and put them in the quar tank to see how they do.
The proactive medication is also done with wild caught fish.
Tolak