Copper Ion vs Chelated Copper Treatments in Aquariums and Ponds (Revised)

Important Notice:  There is new information about the adverse effects of heavy metals on fishes.  Copper is a heavy metal.  Therefore, concern has to be given when considering the use of a copper treatment in an aquarium or pond.  See Kordon Article "The Importance of Removing Heavy Metals From Aquarium and Pond Water" for further information.   Kordon will no longer be providing products with copper ingredients for treating                         fishes, because of the scientific evidence that such products are harmful to fishes and aquarium and pond keeping.

Those using copper treatments for aquarium and pond fishes need to understand their use for particular treatments, because while they have special abilities in treating certain external infections, particularly in marine fishes, they have their very serious dangers in use that need to be fully understood.  Unless users understand why the copper treatment they want to use is right for their purpose, they should use the more forgiving treatments that are not as restrictive in treatment requirements, and are less harsh on the aquarium and pond environment. 

For milder Kordon products these would especially include the naphthoquinone organic treatments Ich-Attack®, Prevent-Ich® , and Rid-Fungus™, which do not require water changes, and are safe to use with reef and live rock aquariums.  For the chemical treatments, Kordon Rid-Ich+, Formalin-3® , Malachite Green, and Permoxyn® would be much safer to use.

Copper treatments are used as therapeutic (remedy that cures or restores to health) and prophylactic (remedy that prevents or slows the course of an illness or disease) agents for fishes in both salt and fresh water, particularly for salt water.  It is important to note that the increased level of treatment that is satisfactory in salt water may be destructive to fishes in fresh water.  The copper treatments are specially used for eliminating external infections on fishes by protozoans (single celled), as well as used against external metazoan (multicellular) parasites, such as flukes, although effectiveness varies depending upon the parasites involved.

 To summarize, there are important points that need to be understood about copper treatments.

*   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. 

Therefore, chelated copper treatments are effective (primarily as a preventative) over long time periods.  As the free copper ions are released into the water over time, they are active at first and eventually  become bound to various compounds, thereby becoming inactive.  New free copper ions are gradually released in the water by the chelated copper treatment in the water, which take the place of the bound ions.  Chelated copper treatments are most effective as longer term preventatives, being toxic over time in the water, thereby  inhibiting the actions of disease organisms.

There are references in aquarium and pond keeping to using chelated copper treatments as a preferred treatment of diseases.  Over time in the water with the build up of free copper ions, this might be effective.  However, it is more practical to consider chelated copper treatments as essentially a preventative, because they release copper ions in the water over time, and professionally have been mainly used to prevent diseases from developing. 

Decades ago chelated copper was widely used for several years by some public aquariums for disease suppression in their exhibit tanks.  But as time went by, and the release of copper ions increased from the chelated copper treatment, the ions became toxic to the fishes and invertebrates, particularly so in freshwater tanks.  The treatment was then discontinued.  At that time Kordon's NovAqua was not yet on the market, which could have been used to quickly remove all heavy metals, including copper ions, from the water .  Now, with the NovAqua products, chelated copper treatments can be controlled or eliminated.
 
Copper Ion Products.  As for copper ion treatments, their copper ions are completely free, not bound to any compound, and are totally active when placed in the water.  Over time the ions also become bound to various compounds in the water, thereby eventually becoming inactive.

The proper copper treatment for immediate action against parasites is a product with copper ions.  However, it is a very powerful treatment and needs to be used with caution.  Once copper ions are in solution, whether from chelated copper or copper ion treatments, they remain there and are absorbed by glass, gravel, sand, rocks, coral, various plastics, etc., and stay in the aquarium or pond permanently unless chemically removed.  When there are fluctuations in pH (acidity/alkalinity) in the water, part of the copper that has been absorbed can return to solution and be toxic to the aquatic inhabitants, including the fishes.  This can be the reason for sudden die offs when least expected and for no apparent reason, long after a copper treatment has been used. 

There are published sources for aquatic veterinarians that consider copper therapy not suitable for use by home aquarists for freshwater treatments, because such treatments need to be monitored very carefully and the levels of treatment need to be kept below toxic levels.  If fishes are overdosed, there have been indications that treatment of the fishes in baths or dips with water soluble antibiotics such as tetracycline, metronidazole, or sulfa drugs, may aid recovery. 

We recommend Kordon's NovAqua Plus+ or NovAqua (and its related products Fish Protector (=PolyAqua) be used to remove heavy metals permanently from the water, including copper.  This is particularly helpful after a copper treatment to remove the copper entirely from the aquarium or pond environment. Multiple treatments on successive days will be necessary to remove all of the copper, since the copper needs to be in the ionic form for the NovAquas to be successful in their removal.  (See Kordon Article "The Importance of Removing Heavy Metals From Aquarium and Pond Water" for further important information on dosing with NovAqua+]. 

It is important to understand that as soon as any of the copper treatments are put in the aquarium or pond, the copper ions will start to bind with the substrate, whether glass, gravel, cement, rock, decorations, etc.  The only way to remove the copper from these surfaces, including those of the fishes and other aquatic life, is by the use of such products as one of the Kordon NovAquas that remove heavy metals from the environment. Kordon Fish Protector and  PolyAqua will also remove heavy metals, at or near the full extent that the NovAquas do. 

Copper products are particularly effective on marine single-celled Oodinium and Cryptocaryon, and on a case by case basis may also be effective on multicellular parasites, such as flukes, trematodes, mites, leeches, and worms. 

 In the case of white spot disease or Ich ("Ichthyophthiriosis"), particularly  on freshwater fishes, rather than using the invasive copper treatments, we recommend Kordon's Rid-Ich®+ as the most appropriate chemical treatment for Ich in fishes, and Kordon's organic herbals (Ich Attack®, or Prevent Ich® or Rid Fungus™) for treatments that do not require water changes each time used, and as being the most effective in not harming invertebrates such as in coral reef and live rock tanks.

The Desired Level of Dosage for Copper Ions in the Water for Treatment.  As a general rule the desired level of dosage without considering the adverse effects on the fishes is between 0.15 and 0.25 ppm copper ions in the water.  Less than 0.15 ppm is generally considered less effective in treatments. 

The Effect of Copper on the Nitrogen Cycle and Biological Filtration.  Copper ions adversely affect the gram-positive bacteria of the nitrogen cycle and biological filtration.  The copper continues to affect the bacteria even after the copper treatment is discontinued.  This is considered to be due to the copper remaining in the water system after the treatment, as described in the above account.  This is all the more reason why Kordon NovAqua or NovAqua+ or Fish Protector (=PolyAqua) should be used when the copper treatment is ended in order to eliminate any copper that is present.  During copper treatment, the filter materials used in biological filtration should be removed to keep the filtration bacteria alive.  When this is done, the filter materials need to be placed in water having ample water flow, so that the bacteria get sufficient oxygen to stay alive.   

Adverse Symptoms in Using Copper Treatments on Fishes.   Besides the inherent toxicity of copper treatments, that may affect fishes if overdosed, there may be the drawback of copper ions affecting the fishes' immune system, particularly during shipment.  It is not recommended using copper treatments before, during, or immediately after the fishes' shipment.  the reason being that the fishes' immune system may be naturally impaired from the stress of all the movement that naturally takes place before, during, and after shipping.  Any copper treatment during this time could further disrupt their immune system. 

Symptoms of Overdosing Copper in Fishes.  Overdosing of copper ions in the water affects the fishes' gills, olfactory organs, and internal organs (such as kidneys, liver, immune system).  The fishes become darker in color and become less active, eventually becoming disoriented in their actions and dying.  

Conclusion.  Copper treatments in the chelated and ionic form are very powerful treatments against external infections.  However, they have their serious drawbacks, and are not recommended to be used in aquarium and pond keeping.  Know what you are doing if and when you use copper treatments.  Remove the copper ions immediately after usage by using one of the Kordon NovAquas, Fish Protector, or PolyAqua that removes heavy metals from water, gravel, glass walls of the aquarium, and decorations.  .  Otherwise, in place of copper treatments use treatments easier to handle that are of less potential harm to the fishes, and to the aquarium and pond environment.