Tips when treating fish with copper, that will save your fish!

Copper is a common treatment for many different parasitic diseases in fish, in both freshwater and marine.

Though, saying this, copper is not always the preferred choice for many reasons.

Copper is toxic to certain fish species and invertebrates, and at lower pH.

Where fish can tolerate copper, we are using sufficient amount to kill the parasites, but less than what would kill the fish. The target amount of copper must be maintained at ~0.2 mg/L. There is an art to maintaining this level stable in the water body, for the duration of treatment. And a reliable, easy to use, copper test-kit is a must.

Copper levels may to drop due to adsorption by carbon filtration and so this must be removed. Copper also binds to bicarbonates and carbonates (which is high in marines). This binding of copper may be reversed if salinity increases, so you must maintain salinity.

Ensure you only feed manufactured diet, rather than fresh/frozen crustacea (like brine shrimp) because the latter can bioaccumulate enough copper to be toxic to fish that eat them!

After completion of copper treatment, use carbon to filter it out.

For advice on diagnosis, treatment and test kits, contact The Fish Vet.

Yours sincerely,

Dr Richmond Loh
DipProjMgt, BSc, BVMS, MPhil (Pathology), MANZCVS (Aquatics& Pathobiology), CertAqV, NATA Signatory.

Aquatic Veterinarian & Veterinary Pathologist.

Aquatic Veterinary Medical & Diagnostic Services.
Ph: +61 421 822 383


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