So - some species of flukes are pretty specific to the type of fish they infect. Triggers are quite a bit different in their scale/skin structure than most other aquarium fish. I would not be at all surprised to have a trigger develop a disease that other fish won't catch. My concern here is the worsening of the symptoms. Without an "end game" I'm just worried that things will progress further, to the detriment of the trigger. I do not see any reason that if possible, you couldn't isolate the trigger for treatment alone. I wish I could give the fish a skin scrape and look at it under a scope that would probably tell us pretty quickly what is going on here!
JaY
Thx. X hatch Still looks and behaving fine. Wish I could catch him but there’s is no way without dismantling tank as every time i get near he freaks out. So unlike him as he was eating out of my hand before. Will do a 20% water change and then replenish copper to maintain 2.00 for another week while dosing tank with prazi. Will do another water change in 7 days an start removing copper while adding 2nd dose of prazi. Hopefully 2 prazi doses does it but it can take 3 or 4. Will add extra aeration for sure. Thx again