First of all, DO NOT treat for ich or any other disease unless it is present and you know what disease it is.
Second, the fish should stay in QT for 4 weeks to allow any issues to come up and be resolved. NOw if nothing comes up and they are healthy, go ahead and add them to the tank at the end of the QT period.
Now, if you do have to treat for lets say ich, you need to wait, 7-10 days after the last cyst has dropped off the fish, by cysts I mean the look of the fish being sprinkled in salt. Once that has occurred then about 2-3 days after that, the extra time to make sure it is indeed the end of the infection, then it will be fine to add them to the tank.
Bare in mind though,if you have used medications, then it is best to introduce the fish, as if they are new, by proper acclimation. The QT tank and the display tank should have the same parameters the fish are ultimately going to live in UNLESS you raise the temperature for ich treatment.
If you have fish you still want to acquire and have used medication in the QT tank, then as mentioned, clean it out, with a mild vinegar water solution to make sure any traces of the ich parasite are gone, seed the filter again once cleaned and then begin again.
There is NO rush in this hobby, doing things slowly reaps more rewards than rushing in and buying fish, Patience really is a virtue and goes a long way to providing a stable, healthy environment for your fish to live in for many years to come.
I'm sorry...you misunderstand. I don't plan on blindly treating my qt tank when I get new fish. I meant my main tank. I am treating it right now for Ich, well was treatment ends today. You did answer my question though
Which I am EXTREMELY grateful for!! I cannot believe I didn't join this site sooner...couldve saved myself SOOO many headaches!! I promise not to rush out and buy fish...I just didn't know how long I should wait or even what I should do. As it turns out, almost everything I have done up to this point was wrong. And I lost over half of my fish because I introduced my new male into my main tank the day I got him...stupid. Thank you so much for all your help...