Identification Methods and Correct Usage Techniques for Common Fish Medications

I. Antibacterial Agents (1) Furazolidone, also known as furaltadone. Yellow powder, odorless, with broad-spectrum antibacterial action and relatively low toxicity; can be administered orally or as a bath, mainly used to prevent and treat eel gill rot, enteritis, red fin disease, and red spot disease. For oral administration, mix 15-20 g of the drug per 100 kg of feed, for a course of 3-5 days; for bath treatment, scatter the drug solution over the entire pond at 2 g per cubic meter. Because the drug is poorly soluble in water, it can first be soaked and mixed with alcohol before use. (2) Chloramphenicol. White powdery drug, easily soluble in water, effective against both Gram-negative and Gram-positive bacteria, mainly used to treat eel enteritis, vibriosis, Edwardsiella disease, and skin rot. For oral administration, use 30 g of the drug per 100 kg of feed, feed continuously for 3-5 days for early prevention and treatment. (3) Oxytetracycline. Earth-yellow powder, with antibacterial and bacteriostatic action, can be used to treat various bacterial diseases, mainly orally, using 40 g of the drug per 100 kg of feed, fed continuously for 5-7 days.

II. Insecticides (1) Copper sulfate and ferrous sulfate mixture. The two drugs are transparent blue and green crystals respectively, hence also called blue vitriol and green vitriol; they have strong astringent and insecticidal effects, and are toxic to Sinergasilus, Trichodina, Chilodonella, Glossatella, etc. Use 0.7 g of the drug per cubic meter of water, of which copper sulfate is 0.5 g and ferrous sulfate is 0.2 g. (2) Crystalline trichlorfon. The pure product is a white solid containing 90% active ingredient; it dissolves in water to produce dichlorvos, which can poison and kill various parasites. Use 0.7-1 g of the drug per cubic meter of water; application should be done in the morning, but it must not be used together with alkaline drugs such as lime, so as to avoid poisoning the fish.

III. Insecticidal and Bactericidal Dual-Purpose Agents (1) Formalin. It is a water-soluble medicinal liquid containing 40% formaldehyde, with a strongly pungent odor and strong broad-spectrum insecticidal and bactericidal action. Generally use 25-30 g of the drug per cubic meter of water, and when the disease is severe it can be increased to 40 g; it has good efficacy in preventing and treating eel gill rot, red fin disease, and skin rot and perforation disease in freshwater fish, but the drug readily volatilizes and loses effectiveness in sunlight, so application should be carried out in the evening or at night to improve the insecticidal and sterilizing effect. (2) Potassium permanganate. Purple elongated crystals, easily soluble in water, with strong insecticidal and sterilizing ability, mainly used to kill bacteria and parasites on the body surface of fish.

Medication precautions: (1) Water body measurement and dosage must be calculated correctly. (2) Before medication, first drain part of the pond water, which can save the amount of medication used and reduce costs. (3) After 8 hours of bath treatment, add water or change the water to adjust water quality. (4) If the sick fish swims rapidly in the water after medication, it indicates the concentration is too high, and application should be stopped immediately and the water changed. (5) The medicinal liquid should be scattered evenly, and aerators should be used in coordination to increase oxygen.