Well, a little update. After talking to Robert about the white stringy poop, he suggested I use General Cure. It contains both Prazipro and Metro. Before this, I was just using Metro because I already dose Prazipro for a week. But apparently, I think I need to continue dosing Prazipro, so I'll continue to do it with General Cure. He said the medication must be put in the food because the fish has internal parasites. So the in tank treatment wouldn't be doing much. So my plan is to mix General Cure and Focus into food and feed it until I no longer see white stringy poop.
So far, the Regal is eating and is active, so I'm hoping this cocktail can resolve this issue so I can transfer it to my main display. Today the Regal has been in quarantine for three weeks. I'm anticipating perhaps another two weeks. There are no signs of flukes, but I really do want to resolve the internal parasites issue.
Thanks again to all the people who have been providing their feedback and allowing me to keep this gem of a fish! Couldn't have come this far without you guys!