Freshwater fish farming often encounters a number of diseases that are difficult to detect and treat, affecting economic efficiency. If the management of water and food is not well managed, fish diseases can easily arise, leading to mass deaths of diseases. Below are the common diseases and how to prevent and treat in freshwater fish.
1. HYDRAULIC DISEASE (Water mold disease)
The disease occurs in most freshwater fish species such as carp, sesame, grass carp, catfish, floating fish, goby … The disease develops favorably in ponds with stagnant water, content of organic matter. high muscle …
Pathogens: There are some varieties of fungi such as: Leptolegnia, Aphanomices, Sarolegnia, Achlya.
Pathological signs: At first, there are gray-white areas on the skin of the fish, which are small soft mycelia; the fungus then develops into fluffy white tufts. Diseased fish swim abnormally, like to rub against objects in the water, make skin scaly, creating conditions for bacteria to invade. In addition, the parasite can cause acne.
Disease prevention and treatment: Apply pond cleaning technique before each crop. Keep the fish at an appropriate density, avoid mechanical damage or damage by parasites; maintain and stabilize pond temperature in many ways such as maintaining pond water level of 1.5m, covering water hyacinth 2/3, pond surface …
Use fungicides for fish. There are some chemicals that can be used to treat the mycosis: BRONOPOL-FISH 1 ml / 100 liters of water (repeat treatment after 48 hours) or 2 ml / 100 liters of bath water for 2 hours / day (change water or switch tanks later 2 hours), for 3 consecutive days.
2. STREPTOCOCUS DISEASE
The disease occurs in some freshwater fish species such as tilapia, carp … and some marine fish species such as sea bass disease often outbreaks when the weather is at 20 – 30 degrees Celsius. Pathogen: caused by bacteria Streptococcus (streptococci) on all stages of fish development. Pathological signs: Fish color gradually turns dark, swimming is not normal, ankle is protruding, hemorrhage in fins and gill bone. The hemorrhagic sores spread into ulcers, but they are shallower than other types of ulcers. Diseased fish swims, not orientated. The disease in its acute form causes a high mortality rate.
Disease prevention and treatment: Maintain a minimum water level of 1.2 m in the pond; increase water exchange, fan water at night and early morning to provide enough dissolved oxygen for fish.
Periodically add multivitamins to food continuously for 7 days; Water disinfection by IODINE COMPLEX, dosage according to instructions.
Using the method of mixing antibiotics into the feed, such as DOXY 20% FISH Mixing into fish feed continuously for 5-7 days according to the following dose: Mix 4-5g / 1-1.5kg of feed or 1kg / 30-40 tons of fish.
If it is floating food, dissolve the drug with a moderate amount of water, then spray evenly over the food, then coat the outside with ink oil.
3. NEO MIRROR DISEASE
The disease is more common in grass carp, white sesame, white sesame … they parasitize on skin, scales, gills, nasal passages, eye sockets, mouth … The disease thrives in late spring. when the temperature is between 20-25 degrees Celsius.
Pathogen: An anchor worm of the genus Leronaea.
Pathological signs: Diseased fish swim abnormally, slowly, poor appetite, deformed. On the fish body there are small red spots, some parasites in the mouth make the fish mouth swell and not close, it cannot eat.
Prevention and treatment: Application of integrated disease prevention measures. Before stocking, fish should use oval leaves to cover the pond with the amount of 0.2 – 0.3 kg / m3 to kill the larvae of anchor larvae in the pond.
If possible, replace all the water in the pond and disinfect the replacement water.
Using oval leaves of 0.4 – 0.5 kg / m3 of water applied to diseased fish ponds can kill Lernaea parasites. Because the rapidly decomposing oval leaves consume a lot of oxygen and release toxic gases, especially in summer with high temperature, water supply must be monitored promptly when necessary.
Use BRONOPOL Scallop and fingerlings: 1 ml / 100 liters of water (repeat treatment after 48 hours) or 2 ml / 100 liters of bath water for 2 hours / day (change water or change tank after 2 hours), continuously for 3 days.
Caviar: 1 ml / 100 liters of water, 30 minutes per day (from the stage of fertilization to the appearance of the eye point) will limit the fungal infection, increase the incubation r
4. DEPRECIATED SYNDROME
Many different species of fish are affected by this disease, some of which are highly susceptible to the disease such as fruit fish, carp, catfish, and carp … The disease is mainly spread by water flow and disease. movement of fish that carry pathogens.
Pathogens: Because the fungus Alphanomyces Invadan grows deep into the fish meat. There are also other opportunistic pathogens such as viruses, bacteria, and parasites.
Pathological signs: Fish rarely eat, stop eating, slow activity; There are deep sores on the infected fish body, causing the fish to die simultaneously. In large ulcers, the center of the ulcer is gray, where the fungus grows, the surrounding edges are black.
Prevention and treatment: For ulcers, the most effective way to prevent disease is to select fish species with high disease resistance. In addition, there are measures to prevent fungus from entering the pond such as: Clearing the pond before the culture cycle.
During the farming process, every 2 weeks / time