I bought a puffer about 2 months ago, when he was caught he got a bit of a wound on his side. About a month later I noticed clear disks on his body, so I FW dipped him and over 10 parasites came off him. Then 4 days later I did another FW dip and nothing came off. And to be sure I FW dipped all my fish. Then a few weeks later he wasn't looking to well so I did another FW did but nothing came off that I could see but he looked happier. For a few weeks I've noticed he's been quite lethargic but is still eating. Then I could see more parasites so I FW dipped him again last week and even bigger parasites fell off him, they were quite large and took 9 minutes to come off. Now I can still see more on him and don't know what to do? How do I get rid of them? Is he too far gone?? My water has been fine other than my nitrates sit at about 10 because I have a canister filter but I have a protein skimmer now.