I have this blue regal tang in qt with a tomini tang, 9 blue/green chromis, and a yellow coris wrasse. They have been in qt for 5 weeks with copper and I am not sure why the blue tang gets recurring extreme ich/velvet. Whenever nitrates get high in the tank then it gets what I think is either extreme ich or velvet. When I do a water change spots go away then come back like a few days later. All other fish are fine and the copper level is 2.4ppm copper power. Please help I am not sure what to do at this point.@Jay Hemdal