The copper is killing your puffer, Do a huge WC (how much do you usually do weekly?) & add a lot of fresh carbon to the filter. Add Melafix to help rebuild his skin that the copper has damaged. How much did you add? Have you been testing it closely? You never treat any fish with copper in their main tank! You'll never toyally get it out of there.
TREATING PUFFERS WITH ICH
TREATING PUFFERS WITH ICH
