Cupramine effectively eradicates oodinium, cryptocaryon, amyloodinium, ichthyophthirius, and other ectoparasites of both freshwater and marine fish. It is superior to copper sulfate, chloride and citrate: it is non-acidic, less toxic to fish, remains in solution, and does not contaminate the filter bed. It is superior to chelates: it is fully charged (ionic), active at low concentrations, and is removable with carbon.