Sorry to hear that.I will be taking this issue further. It was a terrible easter weekend for us - we lost our fish which we had grown very attached to. By the way I tested 3 different copper tests (Hannah, Salifert and Seachem) and got similar results with all. I believe Oodonex to be dangerous and the dosage on the label to be completely incorrect.
There is another product on the aussie market called Quarantine which is equally dangerous and should be avoided.
The root cause of the problem is the inability obtaining proven copper medication locally due to import restrictions.
Unfortunately, the supplier will probably blame the fish mortality on the disease rather than on their product and it would be pretty much impossible to prove otherwise.