Copper sulphate as a fish disease treatment
Copper sulphate (sulfate) can be used to treat a range of parasites
affecting marine aquarium fish. Protozoan parasites such as Crytocaryon
(marine Ich), Trichodina, Amyloodium (marine
velvet disease) as well as monogenean flukes – Dactylogyrus
(gill flukes) and Gyrodactylus (skin fluke). It is not
recommended for treating freshwater fish.
Copper is active against many marine protozoan and monogenean
parasites, but its use can be complicated. Copper is easily de-activated
because it reacts with calcareous material often found in marine
aquariums, i.e. coral and limestone, to form insoluble copper carbonate.
The solubility of copper is highly dependent on pH. As pH increases
above 7, copper precipitates out of solution – 100x increase for every
one-unit increase in pH. The danger is that should the pH of the tank
drop, that is become more acidic, then the level of ‘free’ copper
can quickly rise to toxic levels as the precipitated copper is
re-dissolved. In addition, organic matter also binds up copper.
When treating parasite disease, the free copper level must be maintained between 0.15 - 0.20
mg/litre. If the concentration drops below this range it will not kill
the parasites. If it rises above this level then it will kill the fish!
Copper will also adversely affect invertebrates. Because of these
complications it is advised never to treat the community tank but instead treat affected fish in a separate hospital tank. Many elasmobranchs are also killed by copper. Elasmobanchs include the sharks, skates and rays.
A stock solution is prepared using 1 gram of copper sulphate (CuSO4.5H2O)
to 250 mls distilled water. This solution now contains 1 mg copper per
millilitre. The initial dose is 0.15 mg copper per litre. Therefore if
the tank contains say 200 litres then the dose required will be 200 x
0.15 mgs copper = 30 grams = 30 mls of stock solution.
The copper level of the tank should be measured immediately and
thereafter twice daily using a test-kit that measures in increments of
at least 0.05 mg/litre. If the residual copper level in the tank drops
below 0.15 mg/litre - then add additional doses of 0/05 mg/ litre of the
stock solution until the optimum level is restored. Using the same
example 200 x 0.05 mgs copper = 10 mgs copper = 10 mls stock solution
Copper can easily be removed by activated carbon
i.e. 5 ppm = 5 mg / litre
mg / litre x
3.785 = mg / gall
i.e 5 mg / litre = 18.9 mg / gall (US)
mg/ litre x 4.546 =
mg / gall
i.e 5 mg / litre = 22.7 mg / gall (UK)
To convert imperial
gallons to US gallons multiply by 1.2
1 ounce = 28.35 grams
1% solution =
10 ml per litre
10 gram per litre
38 gram per
45 gram per gall