It is both an effective algacide and a parasite treatment. The problem with the use of copper is that there is a very thin line that separates effective treatment levels from overdoses, which can kill fish. This fact sheet is designed to explain when copper is used, how it is used, and some precautions to take before using it. There have been some recent efforts to use copper to reduce the abundance of algae that cause off-flavor in catfish, but not enough is known yet to make any definite recommendations. Copper comes in several forms which can be used in water.
Copper sulfate is water soluble, and dissolves fairly easily when mixed with water.
Several companies market copper in liquid and crystal forms that are chelated. Chelated coppers stay in solution longer than copper sulfate, tend to give better algae control, and appear to be safer to fish. When buying a commercially manufactured form of copper, attention should be paid to the percentage of copper in the formula. Equation 1 . If your total alkalinity is less than 50 ppm, copper treatments are not recommended because of the high risk of killing fish.