Here is something I found in a quick 1 second search:
* There are two different copper treatments, one chelated, and the other ionic
* Copper treatments are for treating external fish infections, mainly marine protozoan diseases, and are toxic to most aquatic invertebrates
* Copper treatments, which are with the heavy metal cupric ion, need to be carefully administered so that they are not overdosed
* Chelated copper treatments release copper ions in the water over time, and function as a disease preventative
* Copper ion treatments are fully active as soon as they are put in the water, and are an immediate treatment
* Both copper treatments are mainly for one time treatments, because multiple treatments over successive days could build up excess copper ions in the water that are toxic to fishes
* Copper treatments need to be removed at the end of the treatment, which is done by water changes or far more effectively by the use of
Kordon NovAqua Plus? or
NovAqua? or
Fish Protector? =
PolyAqua products
* Copper treatments are mainly recommended for saltwater conditions, because copper is more toxic to fishes in fresh water
* Excessive copper in the water is harmful to fishes. Dosages need to be done accurately so as not to overdose. If there is an overdose, a Kordon NovAqua product should be used to remove the copper
* When practical, the use of a quarantine or hospital tank is recommended when treating with copper.
Chelated Copper Products. Chelated copper treatments are used to suppress diseases in aquarium keeping, particularly for marine aquarium keeping. The chelated copper is usually a heterocyclic (containing a closed ring of
atoms) compound having a metal ion attached by coordinate bonds to nonmetal ions. This means that the copper ions in the chelated copper treatment are bound to a compound and are inactive. When the treatment is used, the copper ions are released by the heterocyclic compound into the water gradually over time, often over days or longer, thereby becoming active copper ions when released from the compound.
Click here: Kordon LLC - Kordon - Articles - Copper