gaskin,
short answer yes.
long answer and I think it is worth sharing, is I didn't QT anything until the disaster that happened Nov 2010.
at the time, I had 18 fish most of them large angels..some of them I had for 3 years, as displayed in this pic:
then to complete my "masterpiece" I added a 8-9 inch emperor angelfish which I got from a local fish store. Since I had luck of not QT any of the current stock I went with this theory (this would prove out to be the incorrect decision), after a 1.5-2 wks I notice my prize blueface angel looked "constipated" with an extended belly that was red..the blueface died in several days, then my flame, then majestic, then purple tang, in all the only fishes that survived were the blonde naso tang and copperband butterfly.
In all 11 out of 18 fish died because I did not QT the emperor angel..these deaths were preventable if I would have QT the emperor and used PraziPro; cause of death was worms/flukes that were on the emperor. I almost quit the hobby after this, so after a week or so to reflect, I decided I love this hobby so much (I've bee in it for 20yrs) so I decided to restock, but this time I would QT EVERTHING.
So after that day, I get all of my fish online (DiversDen-LiveAquaria) as they are the only ones that do an extensive QT procedure. Is it full safe, no, which is why I still QT fish from there another 3-8 wks..most of it is for observation so recurrence of parasites does not occur AND to get them eating foods that I feed the main tank.
BTW, I still have the blonde naso tang to this day and has taken me this long to rebuild my "angel heaven". To see a list of the fish I have, read this:
https://www.reef2reef.com/forums/large-aquariums-180g/144072-welcome-my-375g-jungle.html
HTH,
Kirk