How Should Fishery Drugs Be Used Correctly? Key Methods Explained

With the rapid development of the aquaculture industry, disease prevention and control problems have become increasingly prominent, making it especially important to master the correct methods of using fishery drugs.

1. Apply fishery drugs according to the symptoms

① Poisoning syndromes, including pesticide poisoning, red tide poisoning, seaweed poisoning, fishery drug poisoning, etc. Different poisoning situations require different handling methods. ② Malnutrition, which is chronic and long-lasting; high-quality feed should be selected, and it must not be misdiagnosed as other diseases. ③ Bacterial-like diseases have the same symptoms as bacterial diseases, and most antibiotics are effective. ④ For viral diseases there is almost no effective treatment method, so prevention should be the main approach. ⑤ There are many types of bacterial diseases, and they are the main targets of prevention and control in aquatic diseases. Disinfection should be carried out promptly, pathogens eliminated, and dead fish properly handled. ⑥ Different protozoan diseases caused by different pathogens require different drugs. ⑦ For treating trematode diseases, special drugs such as Kechongwang, Mieruwang, and Shachong Xianfeng can be selected. ⑧ Fungal diseases include branchiomycosis and saprolegniasis, which are caused by deteriorating water quality; regulating water quality is key.

Within 13 hours of applying fishery drugs, close attention must be paid to the dynamics of the fish population. If abnormalities are found, measures should be taken promptly, and preparations should be made for drainage and adding fresh water for rescue. From the second day onward, inspect the pond once in the morning and once in the evening, recording the condition of the disease and the number of deaths after medication.

2. Methods of using fishery drugs

① Broadcasting method: calculate the dosage and sprinkle it evenly over the whole pond. It is suitable for prevention and treatment and is not affected by appetite, but it is not suitable for drugs with high cost and long half-life. Pay attention to incompatibility and the order of medication. For irregular fish ponds, the dosage is inaccurate, safety is poor, side effects are great, and the water body is easily damaged. ② Feeding method: estimate the feed feeding amount and drug dosage to make medicated bait, dry it, and then feed it. It can exert an absorptive effect and is suitable for the prevention and early treatment of viral, bacterial, parasitic, and nutritional imbalance diseases, especially with obvious effects on organ diseases and expelling internal parasites. However, it is passive administration and depends on active feeding, so it is not very effective for fish with severe illness that have stopped eating. ③ Hanging bag method: weigh out the drug, put it in a bag, choose a hanging location, and add drug regularly. It is used for prevention or on larger water surfaces, but the effect is not as good as whole-pond broadcasting and it affects feeding. ④ Immersion method: place the prepared fishery drug into a suitable container, then put the fish into the medicated liquid, and release them after the drug effect is reached. It uses less drug, saves on drug costs, is not affected by the water environment, and does not pollute the water body. It is suitable for valuable and large fish, but rough handling can easily injure the fish body, and it is inconvenient when the fish are small and numerous. ⑤ Smearing method: when smearing, keep the fish head upward to prevent the drug from flowing into the gills. It uses a small amount of drug, is convenient and safe, and has few side effects. It is suitable for broodstock care, trauma, and local inflammation treatment, but it cannot be used for large-scale medication. ⑥ Injection method: divided into intramuscular injection (insert the needle along the base of the dorsal fin at 30-40 degrees toward the head) and intraperitoneal injection (insert the needle along the inner base of the pelvic fin diagonally toward the pectoral fin, with the depth depending on the size of the fish). The dosage is accurate, absorption is fast and complete, and the effect is good, but it is too troublesome and is only used for induced spawning of broodstock, artificial vaccine injection, when the number of diseased fish is not large, and for valuable species.

3. Precautions

① When purchasing fishery drugs, check the approval number, production batch number, expiration date, withdrawal period, storage method, packaging quantity, etc. In particular, do not buy the wrong fishery drug because of the many confusing names. ② The efficacy of fishery drugs in water is affected by many factors, so the dosage must be adjusted according to the situation or the fishery drug must be replaced. ③ Prohibited fishery drugs include sodium pentachlorophenate, malachite green, chlordimeform, amitraz, lindane, toxaphene, methyltestosterone, diethylstilbestrol, antimony potassium tartrate, olaquindox, methamidophos, methyl parathion, dichlorvos, and benzene hexachloride, etc.