Hondatek
Aquarium Advice Addict
I would still qt it. They probably do a good job observing them while in qt but they have a lot of fish to look after . With ick being such a pain to deal with I would rather be safe then sorry.
Have you ever considered tank transfer method? I prophylacticly treat my new fish, and switched from doing hypo to tank transfer. It is very easy and only takes 12 days, and eliminates ich. I then watch the fish for another two weeks and in they go. I was frustrated as I used both copper and hypo and it took 3 months to get rid of ich on some new arrivals (foxface and kole tang). So when I learned about tank transfer, that is what I've done since, even with a blue tang, she hid a lot and I use a small tank 10 gallon and a 5 gallon bucket to do the treatment. It won't get rid of velvet, so you should observe for two to four more weeks.
I like knowing I'm eliminating the ich, even if I can't see it. I had it show up before on day 21 of QT, almost put the fish in my DT, so no more observing for me. Also, with doing 100% water change every 4 days, you don't have to worry about cycling, just add prime or amquel with the water if needed, I never got ammonia in the four days time. After the last transfer I do 10 days of prazipro to eliminate flukes, etc. Just wanted to offer another option to your QT method, no one should have to deal with the pain of treating ich, a little bit of patience goes a long way.