It is now in the QT tank. There are a couple other fish. I couldn't handle waiting 90 days to put in my first fish. Already set up QT for the ones going forward.
Will I have to clean out and start over on QT tank since he is in there now?
Nothing unusual is obvious in the information you provided.
When setting up a display tank, you may add fish as soon as the ammonia cycle has completed. Several methods are outlined in other threads on the forum. Many can be accomplished in a few days. A QT tank may also be established quickly. See the link below for more information.
With regard to you current situation, if I understand correctly, all of your fish including the wrasse were in you display tank. That's where the potential issue is. I assume none of those fish were QT'd before going into your display tank. If any of them had parasites such as ich, velvet or flukes, then all have been exposed. However, if that is not the diagnosis for the dying fish, we don't really know what the cause is for the death.
If parasites are suspected, the recommended treatment would be to QT all of your fish, treat appropriately with copper and prazi which would take about 5 - 6 weeks, and simultaneously allow the display tank to be fallow (fishless) for 6 -8 weeks.
If we were certain none of the fish carried parasites, including the dying wrasse, you could forgo the fallow period. But, the problem is we do not know what caused the death or if any of the other fish are carriers. The life cycles of the parasites of concern are such that they can survive for an extended period without a host (6 - 8 weeks). If hosts (fish) are present, mild infections can exist indefinitely without obvious signs until the fish has a weakness that allows the parasite to aggressively reproduce and infect the fish.
I agree with
@Jay Hemdal that the wrasse appears moribund. Continue to observe to see if anything becomes more apparent while you decide how you want to proceed.
