Tilapia Topic: Disease Treatment: Copper Sulfate

1. DO NOT USE copper sulfate if invertebrate is present in the system.

2. Total alkalinity should be greater than 50 mg/L.

3. The pH of the water is < 7.1 or a bioassay is proceeded.

4. If salinity is greater then 5 ppt, HAMES suggests you to use chelated soultion rather than copper sulfate granules.

Information

Copper sulfate pentahydrate crystals are considered 100% active.

Granular copper sulfate is widely used as an algacide and for control of common ectoparasites.

The toxicity of the copper ion varies with the species of fish. Tilapia are a hardy species. Copper sulfate is more toxic to invertebrates than fish, thus, consideration must be given on the potential impact on invertebrates in the system before copper treatment is applied.

Copper treatment should only be used in conjunction with a reliable test procedure (commercial calorimetric test kits that are adequate for this purpose are available - see appendix on equipment and test kit sources) to monitor the copper level in the treatment water.

The solubility of copper is influenced by the presence of calcium and carbonate in the water (measured as the CaCO3 alkalinity) and pH.

In freshwater, copper sulfate treatment should not be used if the alkalinity and pH of the water is unknown. Solubility and thus availability of the Cu ion as a fish toxicant varies with alkalinity. Copper forms insoluble copper carbonate precipitates in hard and/or alkaline water.

Citrated and Chelated Copper Sulfate

Salinity above 5 part per thousand will have a total water hardness > 200 ppm. Thus, in brackish or salt water, ie. salinity > 5 ppm, unchelated granular copper sulfate is not recommended for use. Instead, a solution of citrated or chelated copper is preferred.

In brackish to full strength seawater (5 to 35 ppt), the dosage of Cu should be within the range of 0.1 to 0.2 ppm.

Stock Citrated Copper Sulfate Solution: Add three grams of copper sulfate pentahydrate crystals and 2 grams of citric acid monohydrate to a 1 liter graduated cylinder and bring the volume to 750 ml with distilled water. Each ml of the stock Cu solution contains 1 mg of copper.

Forms of copper sulfate used and application methods for treatment

1. Copper sulfate pentahydrate crystal
    

   Weigh-out the desired dosage in grams and dissolve in a beaker/bucket of water from the tank/pond. Apply evenly over the water to achieve rapid mixing.

2. 1 mg/ml copper stock solution Make-up instructions: add three grams of copper sulfate pentahydrate crystals to a 1 liter graduate cylinder and bring the volume to 750 ml with distilled water.
    

   Apply the desired ml of solution to achieve the desired dosage; spread and mix for even dispersion

3. Citrated copper sulfate solution (1mg/ml) Make-up instructions: add 3 grams of copper sulfate pentahydrate and 2 grams of citric acid monohydrate to a 1 liter graduate cylinder and bring the volume to 750 ml with distilled water.
    

   Apply the desired ml of solution to achieve the desired dosage; spread and mix for even dispersion

4. Chelated copper solution Commercially available copper solutions
   1. Copper control
   2. Aquatrine (Cutrine)

   Apply the desired ml of solution to achieve the desired dosage; spread and mix for even dispersion

   Note: For citrated or chelated copper solution: Dosage should not exceed 0.15 ppm unless the user plugs in a higher dosage level.

Information on copper treatment:

Copper sulfate is not approved by the FDA for treatement of fish which will be consumed by humans.

Copper sulfate is widely used as an algacide and for control of some of the protozoan ectoparasites and monogenetic trematodes. Copper toxicity varies with species and age of fish; however, tilapia are, in general, relatively tolerant of copper. Treatment dosages range between 0.1 to 0.2 ppm copper. Therapeutic copper is more toxic to invertebrates than to fish. Thus, if invertebrates are in the system these must be removed before copper is added or do not use copper treatment.

The solubility and thus the toxicity of the copper ion is strongly influenced by the presence of calcium and carbonate (measured as alkalinity) and the pH of the water. In freshwater copper treatment should not be used if the total alkalinity (as CaCO3) is unknown. If total alkalinity is < 50 ppm, copper treatment is not recommended. However, if the treatment is applied proceed only after establishing a safe level by bioassay trials. If the pH of the water is < 7.2 copper treatment should only be used if it has been proceeded by a bioassay.

In marine waters or freshwater of total hardness above 200 ppm copper sulfate is rapidly precipitated and should not be used unless a citrated or chelated form of copper is applied.

We strongly recommend that copper only be used if the level of copper in the treatment water can be monitored at least once a day. Copper test kits suitable for this application are listed in the vendor section. Copper is used as a bath treatment with exposure duration ranging from 24 hrs. to 10 days or more.

Dosage determination.

1. For Copper crystals (CuO4.5H2O)

   Copper dosage is based on the alkalinity and is calculated using the following formula:

   a = mg/l CuO4.5H2O 100 a = total alkalinity in mg/l CaCO3

   DO NOT USE IF TOTAL ALKALINITY IS < 50 mg/l

   If pH of the freshwater is < 7.2 then dosage should be established by bioassay. A dosage starting point for bioassay trial of 0.2 ppm is suggested.

   Application: Copper sulfate pentahydrate crystals can be weighed-out to the desired dosage level in grams and dissolved in sufficient water from the container/pond. Once dissolved the Cu solution can be evenly mixed into the water of the container/pond. Or, copper sulfate pentahydrate crystals can be first dissolved to make a stock solution of known Cu concentration and alliquots of this mixture can be administered to obtain the desired level of Cu for treatment.

   Stock Copper Sulfate Solution: Add three grams of copper sulfate pentahydrate crystals to a 1 liter graduated cylinder and bring the volume to 750 ml with distilled water. Each ml of the stock Cu solution contains 1 mg of copper.
    

2. For citrated or chelated copper solution:

   Dosage should not exceed 0.15 ppm unless the user plugs in a higher dosage level.

Equipment and supplies used in copper treatment:

1. Copper sulfate pentahydrate crystals or a chelated copper sulfate solution
2. Citric acid monohydrate (optional)
3. Copper test kit
4. Gram scale or balance
5. 1 liter graduate cylinder
6. 100 ml and 500 ml graduate cylinders

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