Thanks both.
Well yesterday he was REAL bad, wouldn't eat, and hiding against a rock quivering and shaking, never moved from it all day. I actually considered euthanising him just to end it all. But what stopped me was according to theory, with both hyposalinity and copper treatment, the fish should continue to worsen in appearance for 3 days as existing parasites mature, and then after 3 days they improve as parasites are dropping off and not being replaced. Yesterday was day 3 so I just hoped he made it through the night.
So this morning I rush down to the tank and have a look, and he is swimming around. Greatly reduced amount of whitespot on him, his suffering is nearing an end.
Yeah I really like this fish so :bounce:
Slappers I'm going to try that Salifert product sometime, probably if there is ever a bad outbreak in the main tank.