Treatment
There are only two proven methods for the treatment of Marine "Ich", copper and hyposalinity. Neither method can be used in the presence of elasmobranchs (sharks and rays) or invertebrates and so treatment must be performed in a quarantine or hospital tank. Hyposalinity is the preferred treatment as it is not dangerous to the fish and actually eases osmotic stress on the fish. Hyposalinity can also be performed in the presence of calcareous substrates.
For a more detailed description of hyposalinity, please see: http://www.petsforum.com/personal/trevor-jones/hyposalinity.html"><span style="color: #0000ff;">Hyposalinity</span></a>.
Copper is toxic to both fish and invertebrates and must be used with care. As calcium carbonate absorbs copper, copper cannot be used in tanks with calcareous substrates, such as coral sand or shell grit, or with coral decorations. Copper should not be used in the presence of invertebrates or elasmobranchs. Copper is not very stable in sea water and the levels must be continuously monitored.