Copper sulphate/sulfate (CuSO4) is a common salt of Copper. A very dilute solution of Copper sulphate is used to treat aquarium fish of various parasitic infections, is used as a fungicide and is a Algaecide. However, as the copper ions are also highly toxic to the fish, care must be taken with the dosage.
- Quite a few commerical fish treatments contain CuSO4 though some do not mention this is in the bottle.
- Poly-filter foam can remove Copper from the water.