I no how you feel, just medicate and wait a while to see if they start showing signs of gill flukes again, when they are really infested with them it destroys there gills, my husband fetched a bad batch of cherry bards, in real poor health dark in colour, red inflamed gills and a glossy look to the gills, they are still heavy breathing after two treatment i think the parasite has destroyed the gill to much to save them now, hope you have better luck with yours.