So I've been observing the tank more over the course of the hour and I noticed my tangs (purple and yellow) aren't showing any aggression towards the Idol. Yet my Regal is being a complete punk. What a curious paradox! I would have sworn my tangs would have been the aggressors! But I guess the Idol is somewhat similar size as my tangs.
I'm about to feed some mysis and brine now, so I hope that curbs some of the aggression. Still crossing my fingers, but it seems the Idol has calmed down a bit and is swimming a little more freely.
EDIT: Another interesting thing is that my Yellow and Purple seem to go after my small Potter's Angel more than anything. Very odd since it's about 2". Tiny in comparison to them.