Copper has been demonstrated as an effective treatment for some parasites, including Amyloodinium (AKA marine velvet) and Cryptocaryon (AKA marine "Ich"). The commonly available form of copper for treatment, copper sulfate, is not very stable in seawater and levels can fluctuate between those which are toxic to the fish being treated and those that are not high enough to treat the parasites. It is also not tolerated well by some families of fish. Cupramine™ is a more stable form of copper that is easier and safer to use.

What is Cupramine™

Cupramine™ is a complex of copper and amines. Copper amines complexes are more stable than hydrated copper ions like those produced with straight copper sulfate (Cardeilhac and Whitaker, 1988). (Amines are organic compounds derived from ammonia.)

Dosage level for Cupramine™

Follow the directions on the bottle (1 mL Cupramine™ to 40 L/10.5 US gallons of water), wait an hour or so and measure the concentration of total copper. It should be around 0.25 mg/L (=ppm). If there are no fish that are known to be sensitive to copper, repeat the dosage to bring the concentration of total copper to 0.5 mg/L. Note that if the first dosage resulted in more than 0.25 mg/L, the second dose will need to be smaller. If the first dose resulted in less than 0.25 mg/L, the second dose can be larger. If there are sensitive fish in the tank, wait 24 to 48 hours between dosages to ensure the fish are tolerating the copper.

Test the total copper concentration twice daily for the first few days to ensure the concentration is stable. Once stable (2-3 readings the same), testing can go to daily or every second day. Maintain a total copper concentration of 0.5 mg/L (= ppm) for 21 days. This will ensure the appropriate concentration of free copper to kill the parasites while not adversely affecting the fish.

Note that while Seachem recommend treatment for 14 days, 21 days ensure there are no tomonts that outlast the copper treatment, producing theronts or dinospores at the time when the copper concentration is too low to kill them.

As Cupramine™ is a complex, the total copper present in the water will be much higher than the free copper.


No invertebrates! Invertebrates are very sensitive to copper and even very small concentrations can be lethal (Cardeilhac and Whitaker, 1988). Never use Cupramine™ or any other forms of copper in the presence of invertebrates. It is best to treat in a tank that will not be used to house invertebrates in the future.

No calcium carbonate! Copper is rapidly absorbed by calcium carbonate (Keith, 1981). Calcium carbonate includes live rock, coral skeletons, crush coral and most sands. Keith (1981) found that with coral skeletons, as much as 25% of the copper was absorbed in 4 hours and some sands absorbed more than 50% in 2 hours. This makes it difficult to maintain therapeutic levels of copper. An additional problem with copper and calcium carbonate is that a drop in pH, even small, can result in the release of copper back into solution, possibly causing levels that are toxic to the fish being treated.

The effect of absorption by calcium carbonate is somewhat lessened by the copper-amines complex of Cupramine™, which are more stable and help to maintain correct levels of free copper, however, there is still a danger of absorbed copper leaching out of the calcium carbonate. It is far safer to not have any calcium carbonate present.

Copper can retard or inhibit nitrification.. Bower and Turner (1982) found that copper at 0.3 mg/L inhibited both ammonia and nitrite oxidation. The free copper concentration (as opposed to the typically measured total concentration) when using Cupramine™ is typically less than 0.3 mg/L and inhibition of nitrification is not expected, however, the lower concentrations may still slow nitrification to some extent and ammonia levels should be monitored. One complication of Cupramine™ is that some ammonia test kits may give false readings for ammonia due to the presence of amines. Seachem recommend the use of their MultiTest: Free & Total Ammonia™ kit which does not have this problem.

Copper can suppress the immune system of fish. Cardeilhac et al. (1979) found that among other things, copper could affect the immune system of fish. This will also apply to Cupramine™ and should considered while deciding on treatment options. If the fish are infected something that copper has not been proven as an effective treatment, caution should be exercised and more appropriate treatments should be considered.

Further information

More information about Cupramine™, including FAQ, can be found on the Seachem web site: Cupramine


Bower C.E. and Turner D.T. 1982. Effects of seven chemotheraputic agents on nitrification in closed seawater culture systems. Aquaculture 29:331-345.

Cardeilhac P.T. and Whitaker B.R. 1988. Tropical fish medicine. Copper treatments. Uses and precautions. Vet Clin North Am Small Anim Pract 18:435-448.

Cardeilhac P.T., Simpson C.F., Lovelock R.L., Yosha Calderwood H.W. and Gudat J.C. 1979. Failure of osmoregulation with apparent potassium intoxication in marine teleosts: A primary toxic effect of copper. Aquaculture 17:231-239.

Keith R.E. 1981. Loss of therapeutic copper in closed marine systems. Aquaculture 24:355-362.

Last updated: May 8, 2004