CATDOLL : CATDOLL: How to raise grass carp?

Grass carp (Ctenopharyngodon idellus) belongs to the genus Ctenopharyngodon, subfamily Leucophinae, order Cypriniformes. Common names of grass carp include: grass carp, oil grass carp, grass carp, white grass carp, grass carp, grass root (Northeast), mixed fish, black herring, etc. English name: Grass carp. It inhabits rivers, lakes and ponds in plain areas, generally preferring to live in the middle and lower layers of water and nearshore areas with abundant aquatic plants. It is lively, swims quickly, and often feeds in groups. It is a typical herbivorous fish. It hibernates in deep waters of mainstream streams or lakes. Parent fish have the habit of upstream migration during the reproductive season. It has been transplanted to many countries in Asia, Europe, America and Africa. Because of its rapid growth and wide source of feed, it is one of the four major freshwater carps in China.

Habits:

Grass carp Grass carp generally likes to live in the middle and lower layers of rivers, lakes and other water bodies and near-shore areas with a lot of aquatic plants. It has the habit of migrating between rivers and lakes. Sexually mature individuals spawn in rivers and streams. After spawning, the parents and young fish enter the tributaries and lakes connected to the river. They usually feed and fatten in the flooded shallow grasslands and flooded areas and the affiliated water bodies of the main and tributary rivers (lakes, streams, harbors and other areas with aquatic plants). In winter, they hibernate in the deep waters of the main stream or lakes. Grass carp is lively and swims quickly. It often forages in groups and is greedy. It is a typical herbivorous fish. It feeds on zooplankton in the fry stage, and insects, earthworms, algae and duckweed in the juvenile stage. When the body length reaches about 10 cm or more, it completely feeds on aquatic higher plants, especially grass plants. The types of plants that grass carp feed on vary with the food base in the living environment.

Reproduction

Grass carp (silver carp) The reproduction of grass carp is similar to that of several other domestic fish. Under natural conditions, it cannot spawn in still water. The spawning sites are generally selected at the confluence of rivers, deep troughs on one side of the river bend, and the river sections where the two banks suddenly narrow as suitable spawning sites. The reproductive season is similar to that of silver carp, slightly earlier than that of black carp and bighead carp. The reproductive period is from April to July, and is more concentrated in May. Generally, when the river water rises early and violently, and the water temperature can be stabilized at around 18℃, grass carp spawning is in full swing. The reproductive habits of grass carp are similar to those of other domestic fish. The ovaries of grass carp that have reached maturity hibernate in the third stage of development throughout the winter (December to February). When the water temperature rises to about 15℃ in March and April, the third stage oocytes in the ovaries quickly develop to the fourth stage and begin reproductive migration. During the upstream migration, the oocytes complete their development from the fourth stage to the fifth stage. If they encounter hydrological conditions suitable for spawning during their upstream migration, they will spawn. Usually, spawning takes place in the water layer, and the fish body does not float on the water surface, which is commonly known as "stifled spawning". However, when encountering good reproductive ecological conditions, such as a sudden rise in water levels accompanied by thunderstorms, the male and female fish chase each other in the upper layer of the water, and the "floating row" phenomenon of trembling with their abdomens trembling appears. After the eggs are fertilized, the egg membrane absorbs water and expands, and the egg diameter can reach about 5 mm. They drift downstream and develop best at around 20℃. The fry will hatch in about 30-40 hours.

Growth

Grass carp farming Grass carp grows rapidly. In terms of the entire growth process, the fastest growth period of body length is 1-2 years old, and the fastest growth of weight is 2-3 years old. When the 4-year-old fish reaches sexual maturity, the growth slows down significantly. 1 Winter fish is about 340 mm long and weighs about 750 grams; 2 Winter fish is about 600 mm long and weighs 3.5 kg; 3 Winter fish is about 680 mm long and weighs about 5 kg; 4 Winter fish is about 740 mm long and weighs about 7 kg; 5 Winter fish can reach about 780 mm and weigh about 7.5 kg; the largest individual can reach about 35 kg. Grass carp grows fast and is large, with the largest individual reaching 35 kg. The meat is fat and tender and delicious. Every 100 grams of edible part contains 15.5-26.6 grams of protein, 1.4-8.9 grams of fat, 83-187 kcal of calories, 18-160 mg of calcium, 30-312 mg of phosphorus, 0.7-9.3 mg of iron, 0.03 mg of thiamine, 0.17 mg of riboflavin, and 2.2 mg of niacin. Grass carp is often used as the main stocking object in ponds and lakes, reservoirs, and rivers because of its simple diet, wide source of bait, rapid growth, and high yield. Since the success of artificial induction of spawning and fertilization and hatching technology in 1958, the source of fry and fish species is easy, and it has become the main intensive breeding object in my country. Grass carp is also used by fishermen to stock it outside for one or two years to open up wasteland and weed because it can remove grass in the water and along the coast. Grass carp is called "pioneer" because it can quickly remove various grasses in the water. At the end of the Tang Dynasty in Guangdong, my country, there were records of building ridges on wasteland, irrigating it with rainwater, and stocking grass carp for one or two years to remove weeds and make the fields mature. Grass carp is often mixed with silver carp and bighead carp. Grass carp is fed with green grass, while the feed left in the water and the waste discharged by the grass carp are used to cultivate plankton as feed for the silver carp and bighead carp.

【Farming technology】

[High-efficiency and fast breeding technology for pollution-free grass carp] In the past, conventional breeding of grass carp was mainly based on mixed breeding, which took 3 years to cultivate, with high costs and long capital occupation time. The author summarized and promoted the high-yield, high-efficiency and fast breeding technology for pollution-free grass carp, which is introduced as follows. 1. Pond requirements: The pond area should be 10-20 mu, the water depth should be 2-2.5 meters, and the silt thickness should not exceed 20 cm. Every 10 mu of pond is equipped with 1 3-kilowatt aerator and 1 automatic feeding machine. 2. Pond cleaning: Drain the pond water in winter and freeze it for more than 20 days. 15 days before stocking the fish, the water inlet should be 10-20 cm, and 150 kg of quicklime should be used per mu to clean and disinfect the pond. 3. Stocking of fish: Around the Spring Festival, stock 300 grass carp with a size of 200-250 grams per tail, 300 crucian carp with a size of 15-20 per kilogram, 50 silver carp with a size of 5-6 per kilogram, and 10 bighead carp per mu. Soak and disinfect the fish in 5% salt water for 5-10 minutes before stocking. 4. Feeding: Feed mainly granular feed with a protein content of 28-32%, supplemented by green feed. Feeding follows the principles of "coarse first and fine later" and "four determinations and four observations". Generally, feed twice a day, and it is advisable for the grass carp to eat within 2 hours and be 80% full. From March to June, feed mainly pellet feed with a protein content of 28%, with a daily feeding rate of 3%, and feed green feed in moderation; from July to September, control the amount of pellet feed, with a daily feeding rate of about 1.5%, and the protein content of pellet feed is 28%. Increase the amount of green feed to control the occurrence of fish diseases; from October to November, feed pellet feed with a protein content of 32%. After feeding pellet feed continuously for a period of time, stop feeding pellet feed for 1 week, and feed raw grain feed during the interval. Usually pay attention to adding vitamins and other drugs to the feed in moderation to avoid grass carp suffering from diseases such as hepatobiliary syndrome and causing a large number of deaths. 5. Water quality management: Use the aerator correctly. In sunny and windless weather from June to October, start the aerator for 2 hours from 1 to 3 pm every day, and add oxygen in time in the early morning; oxygen should be added early on consecutive cloudy days. Add new water to the pond in time, and adopt the method of "small discharge, small inlet, and multiple water changes" to gradually control the water quality. From June to September, add new water once every 3-5 days, about 10 cm of water each time, and use 10-20 kg of quicklime to make a slurry and sprinkle it all over the pond once every 15-20 days per acre of water surface and 1 meter of water depth. 6. Disease control: Use the method of "coarse first and fine later, fine and green combined" to feed and control the occurrence of grass carp hepatobiliary syndrome. Common diseases of grass carp include red skin disease, gill rot disease, and enteritis. Generally, a combination of oral and external treatment is adopted. External spraying is mainly based on disinfectants such as bleaching powder and chlorine dioxide, which are used for 3 consecutive days; oral administration with "three yellow powder" bait has a better effect. For every 50 kg of fish body weight, use 0.3 kg of three yellow powder (50% rhubarb, 30% phellodendron, 20% scutellaria, crushed into powder and stirred evenly) and mix it with flour paste and mix it into the feed for feeding, and use it for 3-5 consecutive days. 7. Timely fishing: timely catching large-sized adult fish is an important measure for high-yield grass carp farming. The main purpose is to reduce the fish carrying capacity of the pond water and promote the rapid growth of pond fish in the later stage. Generally, the fishing is carried out once at the end of July, in the early morning when the water temperature is lower.

【Disease prevention and treatment】

Precautions

Dead grass carp 1. Ponds that have raised grass carp in the past two years, especially those that have suffered from the three diseases of grass carp (enteritis, gill rot, and red skin disease) in the past, should not be used for the cultivation of grass carp. 2. Thoroughly dredge the old fish ponds, and kill the bacteria and viruses by dredging and exposing the pond bottom to the sun, and eliminate the hidden dangers of fish diseases. 3. Ensure the quality of fry. If it is self-bred, it is best to inject the broodstock with inactivated vaccines before breeding. If introduction is required, it is best to introduce it from a national or provincial fry base. 4. The stocking ratio of grass carp to silver carp and crucian carp should be controlled at about 80:20. 5. In the early stage of grass carp breeding, the fry should be domesticated and fed within 5-7 days, and the feed should be sufficient to prevent the fry from being weak due to feed shortage. 6. Concentrated feed must be made of special compound feed for grass carp. Before mid-July (body length is about 10 cm), concentrate feed is mainly used to accelerate the growth of fry; from mid-July to mid-September, reduce the amount of concentrated feed and increase the amount of high-quality green feed, so that the ratio of concentrated feed to green feed is controlled at 1:3-4:9; after mid-September, increase the amount of concentrated feed appropriately, and control the ratio of concentrated feed to green feed at 1:1-1.5. At the same time, from late June to late September, antibacterial drugs should be added to the concentrated feed to prevent fish diseases. 7. Pay attention to daily disinfection management: ⑴ In the early stage of fish seed cultivation, that is, before mid-June, 20-30 kg of quicklime per mu is sprayed once every 15 days. ⑵ From mid-June to mid-September, 0.2-0.25 kg of Anles disinfectant is sprayed once every 10 days. ⑶ In the middle and late stages of breeding, 1 kg of photosynthetic bacteria is sprayed once per mu per month.

Treatment

1. Parasitic fish diseases: such as Chinese worm, three-generation worm, etc., use 0.5 kg of Insect Killer per acre to spray the entire pond, once every other day, and use it twice in a row.

2. Enteritis, gill rot, and red skin disease:

⑴ When a certain number of grass carp have died due to the "three diseases", the amount of concentrated feed should be reduced immediately or no concentrated feed or green feed should be fed. After 3-5 days of stopping feeding, feed a small amount of green feed mixed with enteritis gill rot, and then gradually increase the amount of green feed. After the fish disease is relieved, feed a small amount of concentrated feed again.

⑵ Soak 5 kg of dried rhubarb slices (crushed) per mu in 0.4% ammonia water for more than 14 hours, then sprinkle it over the entire pond and use it for 3 consecutive days.

⑶ Use 0.5 g of 99% pure kanamycin powder to stick to 1 kg of duckweed. The feeding amount is about 1.5% of the fish body weight, and use it for 1 week.

Note: When grass carp are seriously suffering from the "three diseases", avoid using chlorine-containing drugs such as bleaching powder, chlorine dioxide, etc. Otherwise, it will cause the death of a large number of diseased fish.

Fish farming generally starts with the eight characters of "water, species, bait, density, mixing, rotation, prevention, and management". Water refers to water quality, species refers to fish species, bait refers to bait, density refers to breeding density, mixing refers to mixed breeding, rotation refers to rotational catching and releasing, prevention refers to disease prevention, and management refers to daily management. It can be said that these eight characters cover all aspects of farming. The following will specifically explain that fish farming must first be based on these eight characters. If the water quality is not good and the content of various toxic substances is too high, the fish cannot be raised well, so there is a saying that "fish farming must first be based on water". Good water has the characteristics of "fat, active, tender and refreshing". Every year after the pond is dried up, before the water is introduced from the river into the pond, if there is too much bottom mud in the pond, the bottom mud should be pumped out from the pond first, and then the pond bottom should be disinfected and detoxified after being exposed to the sun for a period of time, and then the water from the river should be introduced into the pond.

A simple test of water quality is conducted. Due to the serious pollution now, many water sources are polluted.

If the toxic substances exceed the limit, detoxification must be done first, such as using Soothean (Caril). Then use chemical drugs or microecological preparations.

Water adjustment. Several general water quality indicators:

Nitrite <0.1mg/L, pH 7.5-8.5, molecular ammonia <0.02mg/, dissolved oxygen >4mg/L. Secondly, look at the algae phase. Generally, light green water, oily green or brown, yellow brown are better. If the water is clear, algae should be introduced. Other abnormal colors should be killed and water should be adjusted. The recommended water adjustment product is Haitai Vitality Bacteria. The product contains a large number of various beneficial bacteria, such as Bacillus subtilis, which can decompose large molecular organic compounds into small molecular substances for fish absorption, photosynthetic bacteria can increase dissolved oxygen, and nitrifying bacteria can reduce ammonia nitrogen and nitrite.

After the water is adjusted, fish species need to be introduced. The selection of fish species is the key. Generally, they are disease-free, have uniform body color, no ulcers, scars or spots on the skin, have complete fins, no deformities, and are active and active, making them difficult to catch. The size of the fish should be basically consistent. The growth of fish with uniform size will basically remain the same. Good fish species have strong immunity and are not easy to get sick.

Before stocking, grass carp should be vaccinated against hemorrhagic disease, which is very important for prevention and treatment. In fish ponds that mainly breed the four major carps, grass carp is mixed with bighead carp, silver carp and crucian carp. The water depth should be 1.5 meters in spring and autumn to increase the water temperature, and 2 meters in summer and winter to keep warm.

1,000, bighead carp 60, silver carp 200-250, crucian carp 200-300. As the rent for fish ponds increases year by year, some reach 1,800 yuan per mu per year, so aquaculture users have to increase the density of aquaculture. Due to the increase in aquaculture density, the incidence of diseases also increases, which makes management more difficult.

Generally, the winter seedlings are laid in late March or early April. They are about three inches and two taels in weight. As large fish species are more expensive, it is recommended that fish farmers use small ponds to raise fish in early May, and then release them into large fish ponds after they reach a certain size. This can reduce costs. In the breeding process, the selection and feeding of feed directly affect the growth of fish, and the feed cost accounts for nearly 70% of the total breeding cost. Good feed can make fish grow quickly and healthily. It is generally recommended that farmers use feed produced by large manufacturers. The feed must be fresh, and moldy feed must not be fed. Generally, it is fed according to the four rules: "fixed time, fixed point, fixed quality, and fixed quantity". Timing, except in the summer, in the morning

Once at 10 a.m. and once at 4 p.m., usually 9 a.m. and 5 p.m. in summer.

Fixed point, feeding will be done at a fixed location, and the number of feeding points is generally determined according to the size of the pond. This point should not be set at the downwind outlet, because the water quality at the downwind outlet is poor, and the wind is mainly from the north and south throughout the year. It is generally set on the pond foundation on the east and west sides. Fixed quality means that feed of consistent quality should be fed, and the feed should not be changed easily. Quantitative, the feeding amount of sinking feed granular feed, when the fish is grown, is generally 3% of the total weight of the fish, and the fish is generally fed to eat 70% to 80% full. It can reach 5-8% in the seedling stage. If the weather is hot and muggy, it is not necessary to feed, and it is generally not fed when it rains. Generally, it can be put on the market after it grows 2 kilograms, and it is caught once in early July. Disinfection should be carried out one day before fishing. Generally, chlorine preparations such as chlormethinol are used to spray the whole pond for disinfection. Disinfection is carried out one day after fishing. Shennong 168 is used for disinfection one day after fishing. After fishing once, put the same or slightly more fish as the number of fish caught into the pond. Generally, fishing is done every 20-30 days until the fish that meet the starting specifications are basically all caught. During the entire breeding period, May to September is the peak period for grass carp diseases. The most common disease in grass carp during this period is the four-disease syndrome, namely gill rot, red skin (external bleeding), enteritis (internal bleeding), and hepatobiliary syndrome. Gill rot and red skin may be purely bacterial.

It may also be a bacterial disease caused by parasites, such as wheelworms, oblique tube worms, hairy tube worms, cup worms, ring worms, Ichthyophthirius, Chinese mystica and anchorhead mystica. Generally, those with more mucus on the body surface and gills are secondary bacterial infections caused by the parasite Ichthyophthirius.

Generally speaking, if there are worms, there must be bacteria. Generally, the worms are killed first, and then the bacteria are killed. Use microscopic examination to check what worms are causing the disease. If the protozoa such as wheelworms, oblique tubeworms and hair tubeworms are caused, Huaqiang ivermectin is generally used to remove them, and then Huaqiang Jiuzhou Shennong's povidone iodine is used, which has a good sterilization effect. If the protozoa such as cupworms are caused, use Fibromyalgia (zinc sulfate) plus Blue Water Treasure (chelated copper) to kill them. For Ichthyophthirius, it is generally treated by boiling water with peppers and ginger and then splashing. If the disease is caused by Chinese worms and anchor-headed worms, Shennong 168 is used to kill the worms first, and then povidone iodine is used for sterilization. For worms such as ringworms (more common on rainy days, less on sunny days), use worms (phoxim + trichlorfon) or tobendazole for external use to kill the worms, and then sterilize. For hemorrhagic diseases and enteritis, gold powder + vitamin C is generally used. For tapeworm disease, albendazole is taken orally to kill the worms. Explosive hemorrhagic disease usually occurs in high-temperature weather from July to October. Shennong 168 and Blue Water Treasure are generally used. Prevention should be the main focus during the breeding process. The core of prevention is water adjustment. Fish ponds generally have ducks and pigs. Duck manure and pig manure are discharged into fish ponds to fertilize water and provide bait for filter-feeding fish. At the same time, they can be directly ingested by Luofei, which can save feed costs. However, due to the ammonia nitrogen contained in the manure, it is easy to cause excessive ammonia nitrogen. Usually, the feeding amount is too large, and the bait cannot be eaten by the fish. It is left in the water to ferment and consume oxygen, which causes insufficient dissolved oxygen. In bad weather and rainy days, it is easy to float, and ammonia nitrogen and nitrite poisoning cause a large number of deaths. Be good at using aerators, generally from 1 o'clock to dawn, and from 12 to 3 noon. The dissolved oxygen is low in the early morning and it is easy to float. Turning on the aerator at noon is to maximize the dissolved oxygen.

In case of continuous rainy days, oxygen-enhancing powder should be prepared for emergency use. These measures are only temporary solutions. The fundamental solution is to adjust the water. It is recommended that aquaculture users establish the concept of long-term water adjustment. Using Haitai Vitality Bacteria to adjust the water can keep the water at a good level for a long time. In this case,

Fish are generally less likely to get sick. Even if they do get sick, they are less likely to die. Moreover, fish grow quickly, which can shorten the time it takes to get them to market.

Early feeding, more than 10 days in advance, can also save feed costs. For example, rapid degradation of ammonia nitrogen,

You can use ammonia cleaner plus Shushuian (Kalil), which can quickly degrade ammonia nitrogen in one day. However, general chemical drugs will recur after 1-5 days, that is, the ammonia nitrogen content will rise again. Another method is to use Haitai Vitality Bacteria plus Water Purification Oxygen King or Bio-bottom Modification King (Runxing), which will take effect after 3-5 days, with a long-lasting effect, and can also degrade nitrite. It is recommended that aquaculture users use this method.

It is recommended that aquaculture users should be good at using aerators

The function of the aerator: to increase oxygen (mix the oxygen-rich water on the upper layer with the oxygen-deficient water on the bottom layer, and also add oxygen from the air)

, stirring water (increasing convection between upper and lower water layers, helping to decompose the bottom sediment, allowing the bottom water to contact the air), aeration (allowing ammonia nitrogen, hydrogen sulfide, biogas, etc. to evaporate into the air). Principles of use:

It opens at noon on sunny days, in the early morning on cloudy days, at midnight on rainy days, not in the evening, and opens early at the floating head; it opens long in hot weather, short in cool weather, long in the middle of the night, short at noon, long when the load surface is large, short when the load surface is small, etc. The daily management of aquaculture has been involved in the above description, and the three most important points are: water adjustment, feeding, and the use of aerators.

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