Here is the issue with observation. If the fish is carrying disease, by the time you see something on it, it might be too late.
Having had the pleasure of meeting Mr Velvet back in Feb-March of 2025, it was instant. Lost a lot of fish sadly! Could have been avoided. Velvet at times can kill a fish before you even truly see what is going on. Fact of out hobby now, is that disease is so prevalent one reason is the amount of fish in confined space. That more than likely the fish might have or be carrying diseases.
So why waste the me week? Ich for example might not even show up for two weeks. So in technicality from what I have experienced personally with diseases is that 2 weeks or what it took for LFS fish to show ich. Had I done QT right away that would have been avoided.
I learned to trust the protocol here. And it works well. But to each their own. I just like to stay ahead of the issue. And one week is not enough observation. I think Jay’s protocol is 42 days of a fish being clear to give the clean bill of health. I don’t have that kind of time in my hands to leave it to observation, and I don’t trust a week of observation.