Aquatic parasites are a major difficulty in aquaculture control, and the inaccurate judgment of parasites not only brings waste of drugs, but also delays the timing of treatment and increases the loss of disease outbreaks, so it is very critical to prescribe the right medicine. The following Chengdu Xingwang Animal Pharmaceutical Fish Disease Experts introduce 16 common aquatic parasite (algae) diseases.
First, the parasites directly recognized by the naked eye:
Anchor head fleas, Chinese fleas, sporangia (cysts), coccidiosis (Amys cysts), iodolites (sacs) tapeworms, fish monsters, etc.
Second, the parasites that need microscopy assistance:
Wheel worms, ring worms, oblique tube worms, small melon worms, egg vortex whipworms, compound mouth flukes, etc.
1. Wheelworm disease
Parasitizing the surface of the body and gills, fry may have symptoms of "white head and white mouth" or "galloping horse" (circumnavigation). Sick fish appear as black bodies and swimming alone. Some swim wildly around the pond in groups, often causing a large number of deaths of fry and fingerlings. The chakra parasitic on the surface of the fish slides back and forth on the surface of the fish body, stripping the host's skin tissue cells and gill tissue for nutrition, destroying the skin and gill tissue, affecting the fish's breathing and normal activities. Fry, fingerling stage, which mainly endangers a variety of fish species, the peak season of the epidemic is May to August, and the water temperature is 20-28 ° C. After the diagnosis is confirmed by the microscope, it is necessary to use the wheel worm special killing product for insecticide, re-examination after 3-5 days, and the killing effect is not satisfactory.
2. Oblique tubeworm disease
Parasitizing the gills and body surfaces of fish stimulates the host to secrete a large amount of mucus, so that the surface of the host skin forms a pale or light blue mucus layer, and the tissue is destroyed, affecting the breathing function of the fish. The sick fish has a poor appetite, the fish body is emaciated and blackened, floating on the surface of the water at the edge of the pool as a side lying down, and soon dies. Scraping off the lesion mucus or cutting off the gill filament on a slide, adding a small amount of water under the microscope can observe the cilia movement of the worm body borrowing the abdomen, slowly moving along the gills and skin. It parasitizes a variety of freshwater farmed fish, mainly endangering fry and fingerlings, often causing great economic losses. Ornamental fish are also parasitic. The epidemic season is from March to May every year, and the water temperature suitable for the breeding of inclined tubeworms is 12 to 18 °C, and when the water temperature is as low as 8 to 11 °C, it can still occur in large quantities. After the diagnosis is confirmed with a microscope, it is necessary to use a special killing product for intracula insecticide, re-examination after 3-5 days, and re-killing when the killing effect is not satisfactory.
3. Small melon worm disease (white spot disease)
The surface and gill flaps of the diseased fish are covered with white dotted insect bodies and sacs, which are visible to the naked eye, so it is also called white spot disease. The mucus at the head, trunk and fins on the surface of the body is significantly increased, mixed with the insect body, it seems to have a film, and there is a clear incidence season for small melon worm disease, and spring and autumn are epidemic seasons in the early southern winter. Ponds with high culture density and poor water quality are prone to occur. Without host specificity, any fish can be invaded and developed. The main treatment of this disease is mercury nitrate, mercury acetate, malachite green, formalin, copper sulfate, potassium permanganate and so on. However, the first three will cause drug residue and endanger human health, the state has explicitly banned, and the latter several therapeutic effects have decreased year by year, or even ineffective. (Ornamental fish can take advantage of the weakness of small melon worms that are not tolerant to high temperatures, raise the water temperature to 32 ° C, and then equipped with drug treatment, usually the cure rate can reach more than 90%.) If treated promptly, the cure rate can reach 100%. )
4. Ringworm disease
In large numbers of parasitic ringworms, the gill filament mucus of the diseased fish increases, and the gills are all or partly pale, hindering the breathing of the fish, and sometimes a large number of insect bodies can be seen squeezing out of the gills. The gills are visibly puffy, the gill lids are open, and the sick fish swim slowly until they die. Ringworm disease is a common multiple gill disease. It is mainly transmitted by eggs and larvae, and is endemic in late spring and early summer, where large parasitizations can cause mass death of fry species. It is the most harmful to silver carp, bighead carp and grass carp. After the diagnosis is confirmed with a microscope, it is necessary to use a ringworm special killing product for insecticide, re-examination after 3-5 days, and re-kill when the killing effect is not satisfactory.
5. Three generations of insect disease
A large number of parasitic three-generation insect fish body, there is a layer of gray-white mucus on the skin, the fish body loses its luster, swimming is very abnormal. Loss of appetite, emaciation of fish, difficulty breathing. The sick fish are placed in a Petri dish filled with water, and if you look closely, you can see that the leech-like insects are moving. Three generations of insects parasitize the body surface and gills of fish, and are widely distributed, of which Hubei and Guangdong are more serious. Every spring and summer, it endangers fry and fingerlings. After the diagnosis is confirmed by microscopy, it is necessary to use three generations of insecticidal products for insecticide, re-examination after 3-5 days, and re-killing when the killing effect is not satisfactory.
6. Chinese flea disease
The gill filaments are swollen and whitish at the ends, and many small maggot-like insects are visible to the naked eye. In severe cases, the fish's head is facing downwards and tails upwards. Greater Chinese gills tend to parasitize grass and green fish gills over 2 years of age. Silver carp parasitize on gills of silver carp over 1 year of age, bighead carp. Open the gill, the naked eye can see many small white maggots at the end of the gill silk, namely the Chinese gill. Sick fish jump restlessly in the water, have decreased appetite or do not feed. Silver carp and bighead carp are often exposed to the water after infection with their tail fins in the water, so they are also known as "cocked tail disease"; The gills of the diseased fish are locally inflamed, swollen and whitish in color. In severe infections, sick fish often die of breathing difficulties. The naked eye can see that there are many small white maggots on the gills of fish, that is, Chinese gill disease. This disease can be diagnosed with the naked eye, it is necessary to use Chinese flea special killing products for insecticide, re-examination after 3-5 days, and re-kill when the killing effect is not satisfactory.
7. Anchor head flea disease
The parasitic diseased fish of anchor-headed fleas manifest themselves in anxiety, food loss, and weight loss. The insect body parasitizes in various parts of the fish body, is white-lined and swims with the fish. Some insects have cotton wool moss on their bodies, which are often mistaken for moss and hang on fish. This pest is ferocious and gluttonous, there will be irregular deep holes in the parasite, the head of the insect drills into the muscles of the fish body, sucks blood with the mouthparts, and also eats scales and muscles, and the scales near the wound are dissolved and corroded into irregular shaped gaps by the secretions of anchor fleas, which opens a convenient door for the invasion of water mold, wheel worms, etc. Therefore, diseased fish that are parasitized by anchor-headed fleas tend to be complicated by other diseases. Anchorhead flea disease is an invasive fish disease. It is a species of arthropod crustaceans , only females parasitize on fish bodies , about 1 cm long. This disease can be diagnosed with the naked eye, and it is necessary to use anchor flea special killing products for insecticide, re-examination after 3-5 days, and re-kill when the killing effect is not satisfactory.
8. Ovalesis
The gills of the diseased fish have many small white dots on the surface of the gills, followed by the body surface and fins, etc., and initially the sick fish huddled together in the pool or formed several circles on the surface of the water to swim endlessly. As the disease worsened, the fish eventually weakened and died. Easy to be confused with small melon worm disease affects the accurate use of drugs, production of important attention to microscopic identification, the need to use effective products for the egg planarian whipworm insecticide, 3-5 days after re-examination, killing effect is not satisfactory when the need to re-kill.
9. Yellow jaw fish rot head disease
The sick fish have a loss of appetite, swim alone, bleed red in the middle of the head in the later stages, form a banded bulge or hemorrhagic ulcer directly above the skull, severe perforation of the head, and cracking of the skull. The disease is mostly caused by bacterial co-occurrence caused by parasites such as rotifers. It is caused by chronic infection of "Edwardian bacteria". The route of infection is through the nasal cavity infection of olfactory cells, and then into the brain, transencenal infection of the skull. The disease occurs with other diseases, the most common being sepsis, which is prone to split head disease after sepsis. Generally, as long as you see the "little red" symptom on the top of the fish's head, you can judge the disease. However, due to the weakness of the sick fish, a large number of wheelworms are often parasitic on the gills, so some people often misdiagnose it as wheelworm disease, but this is only a secondary infection of the parasite. The killing of rotifers and the treatment of bacterial diseases need to be considered together.
10. Madness
The pathogen is silver iodine bubble worm, the diseased fish is extremely emaciated, the body color is dull and dull, the tail is upturned, swimming wildly in the water, playing in circles. Sometimes I burrow into the water and jump out of the water again, like crazy. Loss of normal activity and ability to feed, gradually dying. Opening the skull of the diseased fish, white-spotted myxosporid sacs are visible. Silver carp madness disease is also known as mad knife disease, water disease. It mainly harms silver carp over one year old, deprives it of its commercial value, and causes serious deaths, and the treatment of this disease requires effective killing of iodine bubble worms.
11. Compound fluke disease
The brain of the sick fish is congested, the mouth circles are white, and the eyeballs are protruding or even falling off. Some diseased fish have cloudy and milky white eyes. The disease is also known as double-hole trematode disease, which can cause a large number of deaths for fry and summer flower fish species, and spring flakes and fish over one year old, especially pelagic fish, such as silver carp, bighead carp, tuantou bream, etc., cause blindness, eye loss and other diseases. Once the disease occurs, it is difficult to treat, so prevention and control are emphasized. (1) Fish pond clear pond, can be used every 1/15 hectare according to the water depth of 1 meter, with 125 kg of quicklime or 50 kg of tea cake with water clear pond, kill the pond in the vertebral snail. (2) The pathogenesis pool can be sprinkled with copper sulfate (0.7 mg/L) throughout the pool, and it can be continuously sprinkled twice within 24 hours, which can kill the vertebral snail. (3) Use bitter grass or other aquatic grass to target, put it into the water, trap the vertebral snail, take it out the next day, expose it to the sun, and make the snail die. Trapping for several days can control the development of the disease.
12. Fish lice disease
Fish lice is a small crustacean water pest. It resembles a bed bug and is commonly known as a water bug. It generally parasitizes in various parts of the fish body above 2 cm, especially under the abdomen, fins, and tails. Fish lice stab the surface tissue of the fish body with its mouth thorns, sucking up blood and body fluids. Fish lice is an invasive fish disease caused by a parasite that attaches to the surface of ornamental fish. It often occurs in the spring and is one of the common diseases and multiple diseases in fish. When there are fish lice parasitizing, there is a sense of pain because the fish lice destroy the surface tissue of the fish, showing extreme restlessness, or jumping on the face, or swimming sharply, struggling in every way, rolling and other phenomena, which is very painful. Once this disease occurs, it is necessary to use special fish medicine to kill the fish lice.
13. Fish monster disease
The diseased fish has a bean-sized hole at the base of the pectoral fin, and the worm body can be seen in the hole, and the pathogen is Ichthy-oxenus. It parasitizes the body cavity behind the base of the fish's pectoral fin and has a hole to communicate with the outside world. Its larvae can parasitize due to the body surface and gills of juvenile fish. Endanger yarrow, crucian carp, carp, etc. Hyperemia and inflammation of the parasite site seriously affects gonadal development and can cause mass death of juveniles. The disease occurs in larger waters such as reservoirs and lakes, and is rare in ponds.
Precautions:
(1) Thoroughly clear the pond.
(2) In the breeding area near the waters with a high infection rate of fish monsters, do not enter the water from the outside during the breeding season of fish monsters.
(3) When purchasing fish species, if it is found that there are fish monster larvae parasitizing, the crystal enemy insect aqueous solution should be used for medicinal bath.
(4) Strengthen feeding management, maintain excellent water quality, and improve the resistance of fish bodies.
14. Coccidiosis (Emmy's disease)
Seriously infected with the green fish Amyolar disease, the gills are pale, the abdomen is expanded, and on the intestinal wall of the anterior part of the intestine, there are many small white nodule lesions, as if flowering, and the rice-like bulge of the inner wall of the front of the intestine is the coccidial sac. The intestinal duct is particularly large, two or three times larger than normal, and these small nodules are formed by the chaotic sacs of Amyo, and when the intestinal wall is ulcerated and perforated in severe cases, the outer wall of the intestine can also form nodular lesions. The sick fish is blackened, loses appetite, swims slowly and dies. In severe cases, the intestinal wall ulceration is perforated, and the outer wall of the intestine can also form a furuncle lesion. It can also parasitize in the liver tissue, impairing liver function. In all the fish farming areas in the country can be found, silver carp, bighead carp, grass carp, etc. although there are amy worm parasites, but there is no outbreak of epidemic reports, the amyoiasis of bluefish is mainly prevalent in Jiangsu, Zhejiang region, can cause serious losses to one or two instar bluefish, the epidemic season is From April to July, the water temperature suitable for the breeding of emmy worms is 24 to 30 °C, different species of emmy worms have strict selectivity for the host, but the same fish can often parasitize several kinds of amyo. The foregut must be examined and confirmed with a microscope, and then internal deworming must be carried out with aquatic drugs that are effective for coccidiosis.
15. Tongue tapeworm disease
Commonly known as noodle worms, the abdomen of the diseased fish is enlarged, and the colored banded insect body in the body chamber can be seen by cutting the abdomen. After the worm parasitizes in the fish, it causes the fish's abdomen to swell. The insect body of the noodle worm and the internal organs of the fish are closely intertwined, causing the internal organs of the fish to be oppressed and shrink, resulting in the thin body of the fish and finally death. Noodle worms sometimes burrow out of the belly of the fish, and when the fish is seriously ill, it will float on the surface of the water, and the abdomen will be up, which is easy to catch. Once this parasite is found in the intestine, it can be used for internal deworming with aquatic drugs such as albendazole that specifically target tapeworms.
16. Powder disease
The whole body of the sick fish is like a layer of rice noodles. Powdery disease, also known as white scale disease and ovichophyllosis, is a fish disease caused by the parasitizing body surface of eosinophilic oviformes. In the early stage of the disease, the diseased fish is crowded into a clump in the pool, the mucus on the surface of the body increases, and the dorsal fin, tail fin and back appear white dots successively, and then the white dots gradually spread and expand to the tail stalk, the sides of the body, the head, etc., so that the connections overlap, and the whole body is like a layer of powder, so it is called powdering. The onset of fever is long, the infection is rapid, and the mortality rate is high. Summer and autumn are the most prevalent, and grass carp species are the most susceptible to infection. Summer flowers and "winter flake" fingerlings that have just entered the pond are the most susceptible to this disease.
Prevention and control methods:
(1) The fish pond should be thoroughly disinfected, and in the process of fish fingerling breeding, it is regularly sprinkled with quicklime to adjust the phH of the pond water to about 8.
(2) Transfer the diseased fish to the fish pond with slightly alkaline water quality for rearing.
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