Here's to share my experience. 3 of my new fish are in quarantine for 14 days at 1.85ppm copper power. All 3 (regal, desjardini, powder blue tang) are all eating well. After 14 days, the desjardini started twitching and swimming against the flow. I could not see any white spots like velvet or ich. Then he was on his side the next day so I treated with freshwater bath but he did not make it after. So research continues and no article I could find if prazipro can get mixed with copper power in case on flukes.it justvsaid it's okay but not recommended. I didn't want to lose my 2 remaining fish. It's hard to find a regal that eats all types of food. If I wait to remove copper, it might be too late so I went ahead and added the prazipro. Happy to say that both are doing better. The powder blue was almost going next but he appears to have recovered after the prazipro. Anyway that's my experience in this stressful and expensive but rewarding hobby.