I sold my PBT so I have room in the frag tank for my Next Regal angel. I will keep him there until he eat well, then release him into the main tank. The last Regal angel was harassed to death my my current Regal angel. The tangs and the other fish leave him alone other than the first hr or so. He was very small (<2 inches)l, smaller than my current Regal (around 2.5 inches) When he died, there was no disease other than torn fins from the other Regal. I had such an easy time with my first Regal, that I was cocky and over confident. None of the fish bother him. He was grazing the rock after a few hours and eating frozen food the next day. By day 4 he was aggressively eating food, compete with other fish in the tank for food. Now he eat both frozen and dry food.
My mistake was thinking Regal angels tolerate each other well. There are several people on this thread have 3 Regal angels in their tank.
To remedy this, I will get a medium Regal angel instead of small. I will keep him in the Frag tank by himself (with a lawn mower blenny) until he eats well before I release him into the DT.
I actually have a Medium Red Sea Regal angel coming this week.