How to Identify and Prevent Common Similar Fish Diseases?
Fish farmers all have one headache, and that is fish diseases. How should many common similar fish diseases be identified, and how should they be prevented and treated? Below, the Tutuliu.com editor will take everyone to have a look.
1. Intestinal bleeding
Grass carp hemorrhagic disease and bacterial enteritis have extremely similar early external symptoms. Sick fish have a blackened body color, slight congestion or bleeding on the body surface, swim alone away from the group, move slowly, and have reduced appetite. When the fish belly is cut open, both show intestinal wall congestion. The difference is that during biopsy, the former has better intestinal wall elasticity and less mucus in the intestinal cavity, and microscopic examination shows a large number of red blood cells and sheets of shed epithelial cells in the intestinal cavity; while the latter has poorer intestinal wall elasticity and more mucus in the intestinal cavity, and microscopic examination finds fewer red blood cells in the intestinal cavity and some necrotic and shed epithelial cells.
To prevent and treat grass carp hemorrhagic disease, for each cubic meter of water, 0.3 g of chlorine dioxide can be mixed with water and splashed over the whole pond, and used again the next day; at the same time, for each 100 kg of fish, use 0.5 kg each of rhubarb, skullcap, phellodendron and isatis root daily, plus 0.5 kg of salt, mix with feed and feed, for 7 consecutive days; or for each 100 kg of fish, use 500 g of Sanhuang powder (50% rhubarb, 30% phellodendron, 20% skullcap) mixed with feed and feed, with 3 consecutive days as one treatment course, and use 2-3 consecutive courses according to the treatment effect. To prevent and treat bacterial enteritis, for each cubic meter of water, 1 g of bleaching powder or 0.3 g of Youqijing can be mixed with water and splashed over the whole pond; at the same time, for each 100 kg of fish, use 0.5-1 g of allicin mixed into 10 kg of concentrated feed and feed, once a day, with 3 consecutive days as one treatment course, and use 2 consecutive courses. Or for each 100 kg of fish, use 2 kg of dried Andrographis paniculata (3 kg of fresh grass) daily, beat into a pulp, then add 50-100 g of salt, mix with feed, and feed in 2 portions, for 3 consecutive days.
2. Gill rot
Gill mold disease, bacterial gill rot disease and parasitic gill rot disease have basically similar external symptoms. Sick fish have a blackened body color, especially on the head, increased mucus on the gills, and swollen gill filaments. In severe cases, the ends of the gill filaments are damaged and the cartilage is exposed. In the late stage of the disease, the three are easy to distinguish. In bacterial gill rot disease, the epidermal tissue inside the gill cover becomes inflamed and congested, and the middle part rots into an irregular “open skylight”, while the other two do not have this.
If microscopic examination shows a large number of parasites, it is parasitic gill rot disease. If white small worms resembling fly maggots hang from the ends of the gill filaments, it is often Sinergasilus disease. If a large amount of mucus is secreted from the gills, it is cryptobia, ichthyobodo, trichodina, chilodonella, gyrodactylus or dactylogyrus disease. If the gill pieces are whiter than those of normal fish and slightly have small red spots, it is gill mold disease, and microscopic examination shows the pathogen's hyphae growing into the gill lamella tissue or blood vessels and cartilage.
To prevent and treat gill mold disease, for each cubic meter of water, about 30 g of quicklime can be dissolved in water and splashed over the whole pond. Pay attention to adding new water in good time, keep the water quality fresh, and use mixed compost instead of human manure and cow dung to fertilize the water. To prevent and treat bacterial gill rot disease, for each cubic meter of water, 1 g of bleaching powder or 0.3 g of chloroisocyanurate can be mixed with water and splashed over the whole pond. Alternatively, soak 500 g of rhubarb in 10 kg of ammonia water (0.3%) for 12 hours, mix with water and splash over the whole pond, at a concentration of 2.5-3.7 g of rhubarb per cubic meter of water, or crush gallnut, soak it in water, then mix with water and splash over the whole pond, at a concentration of 2-5 g of gallnut per cubic meter of water. To prevent and treat parasitic gill rot disease, for chilodonella, trichodina, ichthyobodo, etc., for each cubic meter of water, use 0.7 g of a mixture of copper sulfate and ferrous sulfate (5:2) mixed with water and splashed over the whole pond; for gill diseases caused by dactylogyrus, gyrodactylus and Sinergasilus, for each cubic meter of water, use 0.2 g of Qiangli Shachongling mixed with water and splashed over the whole pond.
3. White head and white mouth
For bacterial white head and white mouth disease and trichodiniasis, the former has sick fish with a blackened body color, floating by the shore, with the top of the head and around the mouth turning white, and in severe cases rotting, and it often occurs in the fry and summer-fingerling stages; the latter has most or all of the fish body appearing white.
To prevent and treat bacterial white head and white mouth disease, for each cubic meter of water, use 2-4 g of gallnut, soak it in water for 30 minutes, then mix with water and splash over the whole pond; or for each cubic meter of water, use 2.5 g of rhubarb. First put the rhubarb into 20 times its amount of 0.3% ammonia water and soak overnight, then splash the liquid over the whole pond. To prevent and treat trichodiniasis, for each cubic meter of water, use 0.7 g of a mixture of copper sulfate and ferrous sulfate (5:2) and splash it over the whole pond.