Is the fish breathing fast/hard? I presume it isn’t eating? After that length of time in copper, this is unlikely to be a protozoan. Have you treated with praziquantel for flukes?I have been treating several fish for ich. I am using copper power at 2.5ppm. One of the fish, a hippo tang has what looks like large white sores, not as white as ich. He is not doing so well and looks like he won't make it. The are on their 21st day of treatment. What do you think it is?