Identification and Prevention of Common Fish Diseases in koi fish; What diseases are fish susceptible to in four seasons? In spring (March-May in the solar calendar), the temperature rises gradually, generally between 10-20 degrees Celsius, and the water temperature environment is suitable for the growth and reproduction of various pathogens, especially in April-May, which is the high incidence season of fish diseases-"barley yellow". When fry hatch in early spring, fish eggs are prone to water mold; Fish fry mainly suffer from fish diseases, such as rotifer, melon worm, dactylophora, trematode and fish lice. In spring, adult fish are prone to microbial fish diseases, such as viral hemorrhagic disease, enteritis, gill rot, printing disease, silver carp iodosporosis and so on. In summer (June-August in the solar calendar), the temperature is generally between 26 and 28 degrees Celsius, and the incidence of fish is slightly less than that in spring. At this time, the fish species gradually grow up and their disease resistance is enhanced. Therefore, the fish diseases of ciliates and flagellates are gradually decreasing. In addition, according to the investigation, there are still microbial fish diseases in spring and summer, such as gill rot, hemorrhagic disease, erythroderma, enteritis, printing disease and so on. At this time, it is more common for parasites to have anchor head disease. In midsummer, high-yield ponds are often prone to flooding. In autumn (Gregorian calendar 9- 10), the temperature drops gradually, generally between 23- 15 degrees Celsius, and the water temperature environment is basically similar to that in spring, especially in August-September, which is the season with high incidence of fish diseases-"Bailuxin". Summer flower fish mainly suffer from fish diseases such as rotifer, melon worm, giant salamander, trematode and fish lice. In winter (Gregorian calendar1February-February), the temperature is low, generally between 3-6 degrees Celsius, and fish diseases rarely occur. Winter is the stocking period of fish species, and fish bodies are often scratched by pulling nets or transportation, and water mold can also occur; When the water temperature is high, it is possible to produce flagellates and cucurbits. When the water temperature of the overwintering fish is lower than 10℃, the temperature difference between the indoor air temperature and the water temperature is too large, which causes the fish to be frostbitten when floating due to lack of oxygen. At present, with the change of temperature in spring, summer, autumn and winter, there are 12 kinds of common fish diseases, among which there are 7 kinds of parasitic diseases: trypanosomiasis, cucurbitaceae, giant salamander, anchovy, ichthyosis, silver carp iodosporosis and China herring disease; There are five kinds of microbial diseases: hemorrhagic disease (erythroderma), enteritis, gill rot, printing disease and water mold. As the saying goes, "fish farming is not bad, but it is dizzy with wealth." In fish farming, once fish diseases occur, it will affect the growth and development of fish, and in severe cases, some fish will die. Therefore, we must attach importance to the prevention and treatment of fish diseases and actively implement the policy of "early prevention without disease and early treatment with disease". It is shaped like a pine cone, and the water in the scale capsule can be sprayed out by pressing it gently with your hand. Sometimes the fin base is congested, and the abdomen swells from May to August to produce blood diseases. Muscle type and red fin red gill cover type (1) red muscle type: the lesions are located in the muscles on both sides of the fish, and the fin base, mouth, especially the gluteal fin base are congested, and sometimes the eyes are congested, and the muscles are dotted to varying degrees; The muscles of the seriously ill patients are flushed, and sometimes even the fish are slightly swollen and the skin is red. It can be judged that the muscle is heavily congested and there is no peeling. (2) Red fin and red gill cover type: At the beginning, the fin base was congested, and the gill cover, abdomen and mouth were also congested to varying degrees. In severe cases, the fins and body surface will also be congested. Intestinal inflammation and erythroderma usually occur on both sides and abdomen of fish from May to July. Inflammation, bleeding, desquamation, finger congestion and final decay often occur. From May to July, sick fish move slowly, their body color is slightly black, and their heads and mouths are white. It is easy to identify the symptoms of the disease by observing the movement of sick fish in the pool. From May to July, the lesions were on both sides of the fish. At the beginning of the disease, the bleeding focus is generally round or oval, which seems to have imprint. With the gradual expansion of the lesion, it develops deep at the same time. In severe cases, some diseased muscles often rot. It can be seen that the skin from the back of dorsal fin to the end of tail stalk is white and foggy from May to July. Touch by hand, the scales are rough and there is no mucus. A fish that is seriously ill and dying is furuncle, with its head down and its tail up. From May to July, the lesions were on both sides of the back, showing thick swelling and slight protrusion, which was elastic when touched by hand. By cutting open the affected part, we can see that muscle congestion and saprophytic mold grow a lot of cotton-wool hyphae in the affected part all the year round, and groups of trichinosis mainly harm fry and fish species from May to July. When a large number of pathogens invade, bright and active worms can be seen with the help of a magnifying glass. The symptoms of sick fish are: increased mucus on the body surface, sometimes with sludge, thin and black body, slowly floating on the downwind water. From May to July, when cryptoflagelliasis, kidney bean worm, trypanosomiasis and melon disease were seriously infected, white spots appeared on the skin. So it is also called "white spot disease". Uterine nematodiasis parasitizes under the scales and fins of various fins from May to July. Can be observed with the naked eye. Because the insect body is bright red, it is also called "red line disease". Hookworm larvae parasitize the fins, gills, mouths and mouths of fish for 5-7 months. Careful observation with naked eyes showed that a large amount of mucus appeared on the body surface of the third generation of Trigonella oryzae from May to July. Careful observation of the lesion with naked eyes shows that the worm parasitizes on the body surface during the creeping anchor head disease from May to July, which is easy to see, because the anchor fish uses its head horn and part of its chest to drill into the muscle tissue and fish scales, exposing its slender body to the outside, so it is also called "cold head disease". Infected fish often show anxiety from May to July. Worms are large, usually white and visible to the naked eye, but they often leave their original hosts at any time to find new hosts. Therefore, sometimes they can't be seen in sick fish, and chalking often occurs in acidic water from May to September. At the beginning of the disease, the mucus on the body surface of the sick fish increased, and a large number of white spots and a small number of red spots appeared, and the appetite decreased. In the later stage, the white spots overlap and cover the whole body like rice flour, and the "powder cake" falls off or festers, and the cheeks are also diseased. Sick fish usually float on the water and can't eat or move. Rotten gill disease occurred from July to September. In severe cases, the cartilage at the end of the gill is exposed, and sludge is often carried on the gill. The inner epidermis of the gill cover near the diseased part is often corroded into a round or irregular transparent window (commonly known as "skylight"). Branchial mildew occurs from May to September, with pale gills, sometimes a little congestion or bleeding, and often sudden death. There is a danger of total annihilation. Due to the proliferation and harassment of larvae, the gill of sick fish produces a lot of mucus, which seriously affects the breathing of fish. So the floating time is prolonged, and when the sick fish is seriously black, it swims alone. When a large number of Trichinella spiralis were infected from May to July, the gill was obviously swollen, the gill cover was slightly opened, the mucus increased, and the gill filaments were dark gray. The ends of the gill filaments of some large worms, which are visible to the naked eye, are swollen and white from May to July, and many worms are parasitic in these swollen gill filaments, which can be easily seen by the naked eye. Because there is a pair of slender white egg sacs behind the worm, which are slightly like small maggots, they have the viscera of "gill maggot disease" The anus is red and swollen from May to September. In severe cases, the fin root is congested and erythema appears in the abdomen. When the fish belly is cut open, ascites often flows out and the intestine is inflamed. In severe cases, the whole intestine is red or purple. From May to July, the pathogen of coccidiosis invaded the intestine, and the symptoms of sick fish were pale gill filaments and loss of appetite. There are many white spot cysts on the inner and outer walls of the intestine with naked eyes, and the intestinal tissue is seriously damaged, causing inflammation and congestion, and even perforation of Myxosporidia on the intestinal wall. From May to September, some species only grow and develop in intestinal mucosa, forming leukoplakia bursa. Some species not only invade intestinal mucosa, but also penetrate intestinal wall, resulting in a large number of cysts. This situation is more common in second-year-old carp and crucian carp. Silver carp and bighead carp are mainly infected in winter and spring. Pathogens attack the brain of fish and destroy the normal physiological activities of the nervous system. When a fish is seriously ill, it swims wildly in the water, twitches and turns around, sinks to the bottom for a while, and floats to the surface for a while. The diseased fish head is generally thin, the tail is upturned, the head is yellow, the blood vessels in the brain are bleeding, the liver is generally purple, and sometimes there is water in the abdominal cavity. Because the intestinal tract of fry is blocked by trematodes, which affects the normal feeding and digestion of fry, the sick fish are black and slow-moving, floating in groups on the leeward side, commonly known as "closed disease". Careful observation of the intestinal tract of fry with the naked eye shows that after the fry is infected with cercaria from May to September, the sesame-like worm initially swims up and down on the water surface, showing rapid swimming or struggle, and then the abdomen is upside down and the head is down. He died in a few minutes or ten minutes. The head of the sick fish is congested, and some fish are bent. Some sick fish are also called "cataracts" because they are infected with a small amount of cercaria for a period of time, but the cercaria enters the lens of the eyeball, making it cloudy and milky. At this stage, except for blindness or blindness, fish can continue to grow. From May to September, only grass carp species within 10 cm were infected. After suffering from this disease, the nutrition of fish is consumed, which affects the growth and development, and makes the sick fish lose weight and die. Often in the autumn wind, a large number of fish species die when their appetite decreases. Cut open the belly of the fish, and at the corner of the back of the foregut, many white thin-line worms can be seen with the naked eye. The fish infected in May-September has a large abdomen and a thin back. By gently pressing the abdomen, white worms can be squeezed out from the anus. Cut open the belly of the fish and you can see the worms entangled in the abdominal cavity. Strange diseases of fish from May to September, worms parasitize the abdominal cavity of fish. Careful observation shows that there is a hole the size of a soybean grain at the root of the pectoral fin of the fish. Cut open the belly of the fish from the position of the hole, and there are a pair of white worms shaped like turtles in the abdominal cavity of the fin. The fish suffering from this disease are emaciated and grow slowly, and other horse racing diseases mostly occur in the fry and fingerling cultivation period from May to June. Pond fish swim around the pond for a long time, like "horse racing" From May to June, there are bubbles in the intestine, or there are many bubbles on the body surface and fins, which make the fish float on the water and cannot sink. Shrinkage 10 ~ 3 months, the fish body is shriveled, the head is big and the tail is small, and the back is like a curved blade. From June to July, the fish body bends, sometimes the skull, palate and fins.
Commonly used drugs and precautions 1, furacilin, also known as furacilin. It is lemon yellow crystalline powder, odorless, bitter in taste and slightly soluble in water. It has a strong killing effect on gram-negative bacteria, and bacteria have no resistance to this drug, so it is a common drug for treating bacterial diseases. 2. Copper sulfate (CUSO4*5H2O) Copper sulfate, also known as blue alum and bile alum, contains five molecules of crystal water and is a transparent dark blue crystal or powder. When it loses moisture in the air, it turns white, and then turns blue after absorbing moisture. If it is too wet, it can deliquesce, but it does not affect the efficacy. Copper sulfate is easily soluble in water, and its aqueous solution is weakly acidic, which has astringent effect and strong ability to kill pathogens. Its bactericidal ability is often affected by various factors in water, so the dosage should be flexibly controlled according to the specific situation. It is generally believed that the more organic matter in the pond water, the lower the water temperature and the higher the PH value, the less toxic copper sulfate and the greater the safe concentration, while the higher the water temperature, the lower the PH value and the less organic matter, the greater the toxicity and the smaller the safe concentration of copper sulfate. Copper sulfate can kill a variety of protozoa and fleas parasitic on fish, and it is a commonly used external medicine. However, due to the residual poison (copper can remain in gill, muscle, liver and kidney tissues of fish) and affect the feeding and growth of fish, it can not be used often. In addition, the safe concentration range of copper sulfate is small, so it is necessary to accurately measure the water body when using it. The temperature of water in which copper sulfate is dissolved should not exceed 60℃, otherwise it is easy to fail. 3. Ferrous sulfate (FESO4*7H2O), also known as copperas and ferrites, contains seven crystalline water molecules. Transparent, light green crystal or powder, odorless, astringent, easily weathered in dry air. It is easy to oxidize and hydrolyze in humid air to produce yellow-brown insoluble basic ferric sulfate, which has no medicinal value. Therefore, it should be sealed against moisture. As an auxiliary drug, ferrous sulfate has astringent effect. Mainly for drugs such as copper sulfate to kill parasites and remove obstacles. 4. Trichlorfon (C4H8CL3O4P) The chemical name of this drug is 0,0-dimethyl (2,2,2-trichloro-1- hydroxyethyl) phosphate, which is an organophosphorus pesticide with high efficiency and low toxicity and is widely used in agriculture, animal husbandry and health fields. It is more soluble in water. It is stable under acidic conditions and can be quickly decomposed into dichlorvos with greater toxicity under alkaline conditions, and will continue to decompose until it has no killing activity. Trichlorfon powder can be used to prevent and treat fish diseases. The effective components are 2.5%, 4%, 25%, 50%, and 90% crystals are commonly used. Trichlorfon is a highly effective pesticide with low toxicity, low residue and short residue time. The mechanism is that organophosphorus controls the binding of cholinesterase transmitted by normal nerve impulses, inhibits the activity of cholinesterase and loses the ability to decompose acetylcholine. Because acetylcholine accumulates in nerve cells, nerve transmission function stops, leading to poisoning death of insects, crustaceans and so on. In the prevention and treatment of fish diseases, trichlorfon is widely used to prevent and control fish diseases caused by crustaceans and parasitic helminthiasis in fish in vitro and intestine. This product is purple-black slender crystal, opaque, with blue metallic luster, odorless and easily soluble in water. As a strong oxidant, it releases oxygen when it meets organic matter, which oxidizes the organic matter, so it has strong bactericidal power and is reduced to manganese dioxide itself. Manganese dioxide can combine with protein to form protein salt complex, so it has astringent effect at low concentration and stimulating and corrosive effect at high concentration. In the prevention and treatment of fish diseases, it is used to prevent and treat the third generation filariasis, dactylosis and anchovy disease. 6. Sodium chloride (NACL) is salt. The prevention and treatment of fish diseases is to kill some ectoparasites, such as protozoa and microorganisms, by osmosis. 7. Copper chloride (CUCL2) is powder blue, which is soluble in water, and its chemical properties are less affected by organic matter than copper sulfate. It is used for killing spinal snails and preventing trematodes and blood trematodes. The dosage should be calculated accurately, and a slight excess may lead to fish poisoning and death. 8. Malachite green (C23H25N2CL), also known as malachite green and benzaldehyde green, is a bright emerald crystal and belongs to triphenylmethane dye. Malachite green is a kind of medicinal dye with strong antibacterial effect, which is easily soluble in water. In the prevention and control of fish diseases, it is used to prevent and control water mold and melon disease, and the effect is good. Malachite green is a photosensitive drug, and its toxicity can increase with the increase of light intensity, so it should be noted that it is not suitable for use when the sun is strong during the day. At the same time, the PH value of the pool water above 9 can not achieve the desired effect. Do not contact with zinc or tinplate utensils to avoid acute poisoning of fish caused by zinc dissolution. Malachite green can't stick to people's skin, let alone their mouths. Malachite green can cause mild inflammation of fish gill and skin epithelial cells; The renal cavity is slightly dilated, and the nuclei of renal tubular wall cells are also enlarged; More importantly, it affects the enzymes in the intestine of fish, reduces the secretion of enzymes, thus affecting the feeding and growth of fish, so it can not be used often. Short for SD. It is white or yellowish crystalline powder, odorless and tasteless, insoluble in water, stable in air, and gradually darkens when exposed to sunlight. Should be sealed and stored in a light-proof container. For internal medicine, the absorption is complete, the body excretes slowly, the effective concentration can be maintained for a long time, and the side effects and toxicity are small. In the prevention and treatment of fish diseases, it is used to treat enteritis and erythroderma, and furazolidone is also called furazolidone. Yellow crystal, tasteless, extremely difficult to dissolve in water. It has broad-spectrum antibacterial effect and anti-insect effect. Low drug resistance, low toxicity and no side effects. It is mainly used to treat intestinal infection, and can be sprayed all over the pool to prevent and treat baldheaded mouth disease and gill rot. 1 1, aureomycin hydrochloride golden yellow crystalline powder, odorless and bitter. It is stable in air, easy to deteriorate when exposed to light, and quickly fails in alkaline solution. Should not be in contact with metal, should be refrigerated. Broad antibacterial spectrum, its main function is bacteriostasis, and it has bactericidal effect at high concentration. Individuals can develop drug resistance, but it is generally not high. In the prevention and treatment of fish diseases, it is used to prevent white skin disease and rotten skin disease. 12, oxytetracycline hydrochloride is also called oxytetracycline hydrochloride. Yellow crystalline powder, odorless, bitter in taste, stable in nature, soluble in water, and ineffective when decomposed under alkaline conditions. The antibacterial spectrum is similar to chlortetracycline hydrochloride, with low toxicity and drug resistance, but it is very slow. It is the same as chlortetracycline hydrochloride in the prevention and treatment of fish diseases. 13, penicillin is also called penicillin. Penicillin salt is light yellow powder, which is easily soluble in water. Extremely unstable, it can decompose quickly when exposed to heat, light or acid and alkali. So pay attention to the expiration date. Penicillin's antibacterial spectrum is not as extensive as sulfonamides, and it has strict selectivity for bacterial action. It mainly acts on gram-positive bacteria and some gram-negative bacteria. It has bacteriostatic effect at low concentration and bactericidal effect at high concentration. In the prevention and treatment of fish diseases, it is mainly used to splash the parent fish into the water during transportation to prevent the water quality from deteriorating during transportation, and intramuscular injection of the parent fish after delivery can prevent bacterial infection. 14, erythromycin This product is light yellow crystalline powder, odorless and bitter. It absorbs moisture in air and is insoluble in water. Erythromycin is alkaline, and its solubility in water is greatly increased after it is combined with organic acids to form salts. This product is stable in dry state and easy to fail in aqueous solution. When it is unstable in acid, the drug effect is obviously reduced below PH 4. The aqueous solution should be stored in cold storage, and it will gradually become ineffective at room temperature. Erythromycin has a stronger effect on Gram-positive bacteria than negative bacteria, and bacteria quickly develop drug resistance to this product, but it is not lasting, and the sensitivity can still be restored after stopping taking the drug for 3-6 months. In the prevention and treatment of fish diseases, white mouth disease and gill rot can be prevented and treated.
Some fish friends' ponds
The head of the female anchovy enters the muscle of the host, causing tissue damage, inflammation and ulcer. Sick fish are restless, lose appetite, lose weight and swim slowly. 6- 10 cm fish can be deformed and out of balance. Protozoa, algae and mold are often attached to worms exposed to fish. When seriously infected, the fish seems to be covered with hemp fibers, which increases the burden on the fish and affects the activity ability of the sick fish. When there are a lot of parasites in the fish's mouth, the sick fish can't close its mouth and die without eating. Fish with small scales, such as silver carp and bighead carp, have swollen and inflamed surrounding tissues due to the parasitism of anchovies, thus forming pomegranate erythema on the skin. When anchovies parasitize fish with large scales, such as grass carp, the lodicule in the parasitic part "eats" into a gap, and the scale is pale, and bloodshot erythema also appears in the parasitic part, but the swelling is generally not obvious. Check the fish before stocking. If anchovies are found to have parasites, remove them first, and then soak them in potassium permanganate before stocking. [Treatment] Visible to the naked eye, take it out with tweezers, and then apply mercuric chloride locally to the wound! Fish louse is a parasitic crustacean, which feeds on goldfish most of the time, and only larvae and adults flow into the water when spawning. There are two suckers on the ventral surface of the fish louse, which are used to adsorb on the goldfish. The needle-shaped mouth is used to pierce the fish and suck blood, which makes the bleeding in the affected area turn red, so it is easy to be infected by bacteria. Unless goldfish are attacked by a large number of fish lice, it is not easy to die of this disease. Organophosphorus insecticide is a specific medicine for fish lice, but it is also harmful to goldfish. The best way is to pull out the fish lice one by one with sharp pliers, or treat them with Sera fish pond insecticide, American insecticide, American trematode special tablet, queen whale parasite insecticide, AZ00 ectoparasite insecticide, etc. Check the fish for bacterial tail rot and fin rot before stocking: the tail rot and fin rot caused by bacteria are highly contagious, starting from the fin and then rotting to death. This fin rot has two symptoms. The first one starts from the edge of the fin and then extends inward. The second one starts from the central part of the fin and spreads in all directions. The affected area turned white and finally fell off. After fish are transported or laid eggs, their body resistance will be weakened, and they are most vulnerable to this disease at this time. Once a sick fish is found, it must be isolated immediately and treated with antibiotics or yellow. When the symptoms of fin rot gradually appear, the treatment method is to replace part of the tank water, clean the filter and add a little salt to the tank, and stop feeding for a few days. The function of salt therapy is to increase the proportion of water, change the osmotic pressure in water, and kill bacteria and other pathogens through the change of osmotic effect. Water mold is also called white disease. Scratched the fish due to careless operation and put it into the overwintering fish pond? A skirt? Hey? Hey? *? *** F ≡？ The body is myxomycetes and myxomycetes, with slender branches. One end of them is attached to the fish skin like a root, and the rest are exposed. The mycelium is 3 cm long, grayish white and soft as cotton wool. At the early stage of the disease, the mucus on the surface of the diseased fish increased, forming a layer of white cocoon. In the late stage of the disease, hyphae penetrate deep into the skin on the body surface, and the mortality rate is very high. 【 Control method 】 Malachite green or methylene blue O.03 can be selected, dissolved in 10kg water, and the sick fish can be soaked for 3-5 minutes, then washed with clear water and put into an aquarium. Perforation can only be cured by repeated medication: the characteristic lesions of sick fish are mainly manifested in the body surface of sick fish, which is manifested by the initial erythema to the later skin and muscle necrosis and ulceration, forming ulcers and perforations. Can occur in the chest, abdomen and tail sides, back of the head, fin roots and so on. , especially on both sides of the body. A sick fish has as few as 1-2 lesions and as many as 7-8 lesions. At first, erythema the size of soybeans appeared on the body surface. This erythema is gradually expanding, the skin at the erythema is red and swollen, the scales are loose, and the base is congested. Then the epidermis erodes, scales fall off, exposing the congested and bleeding dermis, and then the dermis is necrotic and ulcerated to expose the muscles, leaving a pit ulcer focus after the muscles fester. Ulcers vary in size and depth, ranging from 0.2-0.3×0.2-0.5 cm to 2-5× 2-6 cm. The depth of superficial ulcer is only about 0. 1 cm, and the depth can reach 0.6 cm. Due to the different degrees of necrosis of ulcer focus tissue, the ulcer surface is uneven. The ulcer is round, oval or irregular in shape, with irregular edges, irregular bleeding areas in the focus, and some old ulcer focuses are parasitized by water mold. The tissue around the ulcer is congested, red, swollen and scaly. The ulcer that has been formed eventually develops into perforation, and the muscles are completely necrotic and rotten, penetrating the body wall, forming perforation, exposing the body cavity and internal organs, and water rapidly pours into the body cavity, leading to the death of sick fish. Perforations are mostly circular, with small perforation diameters of 1 ~ 2 cm and large perforation diameters of 2 ~ 4 cm. Generally, there is only one perforation on a tail fish, and the remaining bone spurs can be seen at the perforation. The tail ulcer festers to expose the bone. Some sick fish can see exophthalmos. In cases with severe body surface changes, the viscera such as liver, spleen and kidney are congested, swollen and fragile, and more mucus is attached to gill filaments and intestinal mucosa. [Control mode] 1. Fish are put into the box or tang qian, and soaked in 10ppm bleaching powder or 20ppm potassium permanganate for10-15min to disinfect the fish. 2. Avoid damaging the fish during operation. Soak medicine: (1) salt: add 1.5 kg salt to every 50 kg water and soak for 5 minutes. (2) Potassium permanganate: 20ppm immersion 10- 15 minutes. (3) Furazolidone: 0.3g per cubic meter of water, soaking for 1-2 hours. Application: (1) Apply tetracycline or chlortetracycline anti-inflammatory ointment to the affected part of the fish. (2) Mix furacilin or furazolidone with vaseline and apply it to the affected part of the fish. Spinal curvature of young fish is often caused by parasites or genetic defects in the body, while for big fish, the main reason is the damage of nervous system.
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