1. What are the methods of raising fish?
_ growth habits of fish:
_ Fish is a wide-temperature variety of freshwater fish. The range of survival water temperature is wide, and it is suitable for growth water temperature 16 ~ 30 degrees Celsius, which is suitable for aquaculture in most areas of China. As a fierce fish, it feeds on live fish in natural waters. However, in artificial culture, if live bait is still fed, firstly, the breeding cost is high, and secondly, it is necessary to equip a special feeding pond to feed the fish, which is time-consuming and laborious, and the cost is high. Practice shows that _ fish can grow normally after domestication of edible chilled fish pieces, and its domestication usually begins when the fish grows to about 5 cm.
-Growth and reproduction of fish;
_ Fish grow fast and big. If the food intake is normal, the weight of the first-year-old individual is between 1.0 ~ 1.5 kg, the second-year-old individual is 3.5 ~ 5.5 kg, the third-year-old individual is 7.5 ~1.0 kg, and the fourth-year-old individual can reach15.0 ~. After sexual maturity, the body length continues to increase, and the largest individual is 2 meters long and weighs 60 kilograms. Usually, males reach sexual maturity at the age of three, and females reach sexual maturity at the age of four. In the wild state, parent fish lay eggs in April-June, and artificial reproduction is generally carried out in May. _ Fish eggs are floating eggs, which need to drift with the water to complete their development after absorbing water and swelling. A mature female fish with a body length of one meter can conceive 500,000 eggs.
_ Fish culture preparation:
1. Pond conditions: It is best to choose a place with quiet environment, convenient transportation, sufficient water and convenient access to water. Don't have tall trees around the pond, so as not to block the sun and hinder the air circulation. The size of the culture pond is generally 3 ~ 4 mu, and the water depth is about 1.5 ~ 2 meters. It's better to be pond culture. There are a lot of plankton in the earthen pond, which can provide some live bait for silver carp and bighead carp.
2. Breeding equipment: fish should be equipped with necessary oxygen-increasing machinery, in addition, several pumps should be equipped to prepare different nets for fishing summer fish, commercial fish and parent fish. _ Fish have no patience. When fishing, they will run wildly, bump into each other and catch them all. Fish aged 2 years and above should be caught with double nets. The inner layer is a net with smaller mesh, which has certain elasticity and can buffer the collision of fish, and the outer layer is a nylon net with larger mesh.
3. Disinfection of pond cleaning: _ Disinfect pond cleaning before stocking fish, dilute the whole pond with quicklime and add water, and sprinkle about 80 kilograms of quicklime per mu of pond, which can not only kill wild fish and pathogens, but also effectively improve the bottom material and water quality. After disinfection, water can be injected after 2 ~ 3 days of ventilation and exposure.
4. Water quality conditions: _ Fish is a kind of freshwater fish living in rivers and lakes. It is best to raise _ Fish with water from rivers and lakes. This water is rich in plankton and oxygen, which is beneficial to the healthy growth of _ Fish. The pH value of aquaculture water should be kept between 7.0 and 9.0, the ammonia nitrogen content per liter of water should not be higher than 0.03 mg, the salinity should not be higher than 5, the dissolved oxygen content should be kept above 5 mg per liter, and the transparency of water should be above 30 cm.
_ Parent fish culture of fish:
1. Parent fish selection: There are fewer and fewer wild fish now. It is time-consuming and laborious to catch parent fish in rivers, lakes and seas, and often nothing will be found. _ Fish parent fish should generally be introduced from regular fish farmers. If fish has been cultured for many years, you can also choose parent fish from commercial fish. Parent fish should choose healthy, harmless and disease-free mature individuals. The ratio of male to female is 1: 1.5.
2. Intensive culture: Parent fish are generally intensively cultured in a special pond with a soil pool of 6 ~ 10 mu, the water depth is 1.5 m ~ 2 m, and the dissolved oxygen in the water is kept above 5 mg per liter. In rainy days or hot seasons, add 4-8 hours of oxygen every day, mainly between 2 pm and 3 pm or between 1 am and 6 am.
3. Stocking density: the stocking density of parent fish is controlled at about 300kg per mu, and about 250g silver carp can be put in each mu, which can help parent fish improve water quality. If the parent fish has been domesticated, you can eat chilled fish pieces and feed them about 8% of the parent fish's weight every day. If the parent fish is not domesticated, there must be enough live bait fish in the pond, and live fish accounting for 5% of the parent fish's weight should be put into the pond regularly every day.
4. Maturity identification: The female parent fish with good maturity has swollen abdomen, soft and elastic hand feeling, and the swollen reproductive pores are reddish, while when the male fish is sexually mature, white semen usually flows out when it is gently pressed on the abdomen, which will spread out after entering the water. After catching the parent fish, hold the parent fish with a special cloth clip, and don't let it collide, so as not to escape injury. Put a proper amount of water in the plastic bag and put the parent fish in the plastic bag. Then wrap it in cloth, carry it to an oxygenator for oxygenation, and then transport it.
_ Artificial spawning of fish:
1, spawning pond: the spawning pond is a circular cement pond with a radius of 2m, a depth of about 1.5m, a water depth of 1.2m, and a water surface visibility greater than 50cm. 5 ~ 6 parent fish can be placed in each spawning pond. Generally, two women are matched with three men of the same age. If men are younger, you can match more men appropriately.
2. Oxytocin: Every fish has its own oxytocin, and preparing a suitable oxytocin for fish is an important factor to ensure the success of fish reproduction. _ Fish oxytocin consists of carp pituitary, luteinizing hormone A2 for injection and chorionic gonadotropin for injection. The dosage of carp pituitary gland is 2 ~ 3 mg, luteinizing hormone A2 200μg for injection and chorionic gonadotropin 654.38+ 10,000 units for injection.
3, induced labor: female fish multiplied by 0.3 (ml), male fish multiplied by 0.3 halved (ml). If the weight of the female fish is 15 kg, the injection dose is 15 times 0.3, which is 4.5 ml. If it is 15 kg male fish, the injection dose should be 2.25 ml. After spawning, it is necessary to continuously inject water into the spawning pond, open the drain and stimulate the parent fish with circulating water to ensure that the parent fish spawn on time.
4. Fertilization: After the parent fish is fixed, the fish eggs should be squeezed into the basin as soon as possible for several times to ensure that all the fish eggs are produced. After the eggs are squeezed, the male fish semen should be squeezed into the basin in time. During the whole operation, the basin should be shaken constantly to make the sperm and eggs fully fuse and improve the fertilization rate. After insemination, stir it by hand for a few times, then put some water into the basin to make the eggs fully absorb water, and put the fertilized eggs into the incubation ring in time. Every cubic meter of water can put 800 ~ 654.38+0.2 million fish eggs.
5. Hatching: _ In the process of fish hatching, the water depth should be kept at about 1.3 meters, and the water flow speed should be controlled according to the size of the ring. It is best to change the pool water once every half an hour or so. The incubation temperature should be between 22-28 degrees Celsius, and the filter screen should be cleaned several times a day to prevent the net from being blocked by egg membranes or sundries and affecting the water flow exchange. The fertilized egg can hatch into larvae in about 35 hours when the water temperature is 22 ~ 23 degrees Celsius.
_ fry culture:
1. sowing: before stocking, clean the pond for disinfection, and then inject water, with the water depth of1.0 ~1.5m. When putting the fry, first put the plastic bag into the pool water, and pour water on it to let the fry adapt to the temperature of the pool water first. 15 ~ 20 minutes later, it can enter the pond, and 50 ~ 100000 fish can enter the pond per mu.
2. Feeding management: It is enough to feed fry with soybean milk. Soybean milk is not only food for fry, but also provides nutrition for plankton, increases the number of plankton in water and provides live bait for fish. Use 3 ~ 4 kilograms of dried soybeans per mu every day, grind them into soybean milk and sprinkle them all over the pool. When the fry grow to 3.3 cm, they can be sold or transferred to the fingerling stage for cultivation. In production, the fry at this stage are called summer flowers.
_ Fish species:
1, the first stage (3.3 ~ 5cm): use 5 ~ 7 kg of dry soybeans per mu every day, grind them into soybean milk and sprinkle them in the whole pond two or three times a day. At the same time, prepare delicious food for the fish, and cultivate the spilled seedlings of other fish as bait for the fish. When the fry grow to 5 cm, they can be domesticated to eat fish pieces.
2. The second stage (5 ~ 10 cm): _ Fish feed on wild live fish. If fish are still fed with live fish in artificial breeding, it is necessary to set up one or several special feeding ponds to feed the fish, which is costly. The domestication of _ fish is to domesticate _ fish from eating live bait to eating chilled fish pieces. The domestication process should be completed in the domestication pool.
① Pond: Domesticated ponds are rectangular cement ponds with a length of 7m and a width of 4m. Each domesticated pond is equipped with two rectangular cages. This cage is 6 meters long and 0.8 meters wide.
② Feeding: _ Fish are carnivores. For domestication, don't put too many fry in each cage to avoid competition between fry. Usually it is enough to put 2000 tails in a cage.
③ Domestication: feed the prepared live bait for 2 ~ 3 days before feeding the dead fish for 2 ~ 3 days. First, feed the dead fish and live fish together, then feed the dead fish and fish pieces together, and finally gradually feed only fish pieces for 2 ~ 3 days. After 7 ~ 10 domestication, _ fish can eat fish pieces, and then it will be transferred to Datang culture.
_ Fish commercial fish farming:
1. Feeding management: _ Fish commercial fish are fed regularly every day, once in the morning and once in the afternoon. The daily feeding amount is 5 ~ 8% of the fish weight. Fish pieces should be gradually increased with the growth of fish. The size of fish pieces depends on the size of commercial fish.
2. Water quality management: In the process of commercial fish management, oxygen is generally increased for about 2 to 3 hours at noon every day to ensure that the dissolved oxygen in the water is about 5 mg per liter. In rainy days or hot seasons, increase oxygen for about 4-8 hours every day. The PH value of the pool water should be kept between 7.0 and 9.0. If the pH value of the pool water is lower than 7.0, it should be adjusted with quicklime. The dosage of quicklime is 15 ~ 20kg, which should be diluted with water and splashed all over the pool.
3. Graded management: _ Fish commercial fish must be raised in grades in time, and _ fish with similar size and liveliness should be picked out and raised in the same pond, and the small ones should be moved to other ponds for special pond culture.
Second, how big can a fish grow?
Sexually mature 3-4 years old, adult fish lay eggs in the torrent of rivers from April to June. Young fish swim from the river to the attached lake for feeding and fattening, and after the end of autumn, young fish and adult fish go deep into the mainstream riverbed for the winter. The growth is very rapid. After sexual maturity, body length continues to increase. The largest individual is 2 meters long and weighs 60 kilograms.
It grows rapidly, and the 2 nd instar fish weighs 3.5 Jin.
_ Fish grow fast and big. If the food intake is normal, the weight of one-year-old individuals is between 1.0 1.5 kg, that of two-year-old individuals is 3.55.5_, that of three-year-old individuals is 7.51.0 _, and that of four-year-old individuals can reach15.020. After sexual maturity, the body length continues to increase, and the largest individual is 2 meters long and weighs 60 kilograms. Usually, males reach sexual maturity at the age of three, and females reach sexual maturity at the age of four. In the wild state, parent fish lay eggs in April-June, and artificial reproduction is generally carried out in May. _ Fish eggs are floating eggs, which need to drift with the water to complete their development after absorbing water and swelling. A mature female fish with a body length of one meter can conceive 500,000 eggs.
What are the functions and functions of fish?
As early as China's ancient book Compendium of Materia Medica, there were records about _ fish. "Compendium of Materia Medica" wrote: _ Fish was born in rivers and lakes, with a flat belly like a carp, a big mouth like a carp, yellow cheeks like a catfish, and a slightly thinner scale like a trout, weighing up to thirty or forty kilograms. Fish is the most poisonous, and it is in the pool, so you can't raise fish.
_ Fish tastes sweet and warm. Entering the spleen and stomach meridian has the functions of strengthening the spleen and regulating the stomach, warming and stopping vomiting. Mainly used for treating spleen and stomach weakness, nausea and vomiting.