A Detailed Guide to Common Diseases of Rainbow Trout and Their Prevention and Treatment Methods
Rainbow trout is a fish that prefers cold water. Because rainbow trout has delicious meat, a good taste, and a relatively mild fishy odor, it is very popular among many people on the market. Market demand is also being opened up step by step, so in order to meet market demand, the farming area for rainbow trout is also becoming broader and broader. However, the fish disease problems brought about by the farming process are troubling farmers. Many novice farmers do not know what diseases the fish may contract, nor do they know how to prevent and treat them. So today, the editor will give everyone a simple introduction to the common diseases of rainbow trout and their prevention and treatment methods.
1. Infectious pancreatic necrosis
Symptoms: Pancreatic necrosis is mainly caused by the IPN virus, and the onset of the disease is divided into acute and chronic forms. In the early stages of the disease, rainbow trout's appetite decreases, the body gradually turns black, and responsiveness declines. About 30 days after infection, the diseased fish begin to die. Larger fish die first. The belly of the dead fish will appear swollen, and after dissecting the dead fish, it will be found that all the internal organs in the fish body have already necrotized and are accompanied by a foul odor. The eyeballs of the dead fish will also protrude and bleed.
Prevention and treatment measures: Pancreatic necrosis has strong contagiousness, and the mortality rate is very high, reaching more than 90%. If farmers do not pay attention and do not take correct prevention and treatment measures, it will cause huge economic losses. When purchasing fry or fish eggs, strict quarantine must be carried out, and the fish eggs must be disinfected to prevent pathogens from parasitizing the fish eggs and invading. Everything that the fish can come into contact with must be disinfected. If a suspected case is found, immediately use bleaching powder to disinfect the water. After the condition is alleviated, supplement the fish with an appropriate amount of vitamin B1 and vitamin V.
2. Saprolegniasis
Symptoms: Saprolegniasis has a relatively high incidence when rainbow trout is injured and has wounds on its body. Mold in the water enters the fish's internal tissues through the wounds and gradually grows into the muscle tissue. This causes the proteins in the fish's muscle tissue to secrete large amounts of decomposing enzymes, which break down the tissues in the fish body and lead to tissue necrosis. After contracting the disease, the fish becomes restless, refuses to eat, and swims around wildly. If treatment is not timely, it will eventually weaken and die.
Prevention and treatment measures: First, disinfect the environment in which the fish live to reduce the presence of mold in the water, reasonably control farming density, and plan the number of ponds well, so that the injury rate can be effectively reduced during later stocking and harvesting. If an injury occurs, agents such as malachite green ointment can be applied to the wound. Also, if diseased fish are found, the pond water should be replaced immediately, and all diseased fish should be transferred to sterile clean water and raised separately. Bleaching powder can also be used to clean the fish pond.
3. Gyrodactyliasis
Symptoms: Gyrodactyliasis is mainly a parasitic disease caused by Gyrodactylus salaris. Parasites generally attach to the scales, gills, and other epidermal surfaces of rainbow trout. In severe cases, the epidermal tissue and gills will be damaged to varying degrees. The diseased fish begin to breathe rapidly and have a decreased appetite. A layer of white mucus appears on the epidermis, which also has a certain effect on rainbow trout.
Prevention and treatment measures: It is still necessary to ensure that the fish pond is clean and hygienic, and use quicklime to sterilize the fish pond. If diseased fish are found, potassium permanganate can be used for medicated baths for the fry in the pond. This is the best prevention and treatment method for Gyrodactylus.
The above three are the common diseases of rainbow trout and their prevention and treatment measures compiled by the editor. In fact, everyone may also have noticed that the primary prevention method for every disease is to clean the fish pond and spray quicklime for sterilization. In fact, this is mainly because the fish live in water, and we cannot clearly observe every fish, nor can we promptly discover the occurrence of disease. So the most important thing is still prevention. Sometimes you may have to wait until the fish die and float on the water surface before you know the fish has become sick, but by then it is already too late. So I hope everyone will be sure to pay attention to the cleanliness of the fish pond and reduce the incidence of disease.