What role does copper sulfate play in aquaculture?
Copper sulfate plays three roles in aquaculture: first, preventing and treating fish diseases caused by protozoa and fish diseases caused by crustaceans; second, mixing with quicklime water as a fungicide to kill protozoa in the breeding pond; third, preventing and treating fish poisoning caused by Microcystis and Oodinium.
When using copper sulfate, pay attention to the following points:
1. The ability of copper sulfate to kill pathogens varies with changes in the water environment. If the water is relatively fertile and the water temperature is lower, the dosage can be appropriately increased; otherwise, reduce the dosage. At the same time, do not apply the medicine in the morning when fish are gasping at the surface or in the late morning when the water temperature is relatively high; it is best to use it from 16:00 to 18:00 in the afternoon.
2. The safe concentration range of copper sulfate is relatively small. When actually using copper sulfate, an appropriate concentration should be selected according to different cultured species. In general use, the concentration is 0.5×10-6-0.7×10-6 copper sulfate for whole-pond splashing, or soaking with a concentration of 8×10-6 copper sulfate for 20-30 minutes.
3. Copper sulfate is often mixed with ferrous sulfate at a ratio of 5:2. Ferrous sulfate mainly removes attached organisms and clears obstacles for copper sulfate to kill parasites.
4. The water temperature for dissolving copper sulfate should not exceed 60°C, otherwise the medicinal solution easily becomes ineffective.
5. Some parasites (protozoa and sporozoa that form cysts on aquatic animals) cannot be treated with copper sulfate. For example, for ichthyophthiriasis, treatment with copper sulfate is not only ineffective but instead causes Ichthyophthirius to form cysts and multiply in large numbers, worsening the condition.
6. Copper sulfate aqueous solution is corrosive to metals. When dissolving the medicine and splashing the medicine, metal utensils must not be used; plastic, wooden, ceramic, and glass utensils should be used.
7. Copper sulfate must not be used in combination with alkaline drugs, otherwise the efficacy will be reduced.
Copper sulfate has an irritating effect on the stomach and intestines. In mild cases, it causes nausea and vomiting; in severe cases, it causes vomiting blood, abdominal colic, and other conditions. Therefore, protective measures must be taken when using it, and a protective face shield, mask, gloves, and so on should be worn.