First, create a good ecological environment for breeding
1, pond conditions
Water source, water quality, soil quality and surrounding environmental conditions should meet the requirements of pollution-free farming. Pond area and water depth: 4-8 mu, water depth 2-2.5 meters, with as little sludge as possible.
2. Strictly clean and disinfect the pond.
One of the key techniques for raising osmanthus fish is strict pond cleaning and disinfection. Disinfection of pond cleaning should be carried out after cultivating "open bait fish" and osmanthus fragrans fingerlings in tang qian for 8-10 days, preferably about half a month in advance if conditions permit, and the bottom of the pond can be exposed to the sun after disinfection of pond cleaning. Disinfecting drugs for pond cleaning include quicklime, bleaching powder, chlorine dioxide, sodium dichloroisocyanurate, trichloroisocyanuric acid, dichlorohydantoin, bromochlorohydantoin and tea dregs. It is recommended to use 20kg quicklime+Qingtangjing 1 bag/mu for thorough pond cleaning at the beginning of the year.
① Quicklime: Fresh-baked or well-preserved ash blocks are required for dry pond cleaning, and the dosage per mu is125-150kg. The disappearance time of the efficacy of quicklime pond cleaning is 7- 10 day.
② Tea dregs: The tea dregs are cleaned with water. After being crushed, the tea dregs are soaked for 6- 12 hours, and then mixed with water and sprinkled all over the pond. Tea cake has no sterilization and disinfection effect, so it should be used with sterilization and disinfection drugs. 40-45 kg of tea dregs per mu of water surface per meter of water depth, and 0/3.5 kg of drifting powder, or 2500 g of trichloroisocyanuric acid, or 300 g of dibromohydantoin.
Second, stocking healthy and high-quality fish with appropriate specifications
1, the standard of healthy and high-quality osmanthus fish fry:
① Non-inbreeding seedlings; One-ripe or two-ripe seedlings in that year;
② The specifications of seedlings in the same batch and the same pond are neat and consistent;
3 satiety;
④ The body is wide, with large and obvious stripes on the side, and the body color is bright without injury;
⑤ In the natural state, it is clustered underwater and clustered in groups; Except for predation, it does not swim to the surface of the water, and rarely moves, standing still underwater; At rest, the head is slightly inclined downwards and the tail handle is bent. If it is picked up in a basin, it will move lively at first, then it will be still, and it will not lie on its side at the bottom of the pool;
⑥ The deformity rate is less than 3%.
2. Appropriate stocking specifications
It is most suitable to buy osmanthus fragrans fingerlings with specifications of 2.5-3.5cm. The seedlings of osmanthus fragrans with this specification can be cultivated directly in the pond or marked thick, which is cost-effective, convenient to transport, low in transportation cost and high in survival rate. Bought back 2.5-3.5cm osmanthus fingerlings should be cultivated in ponds after the standard thickness is about 10cm or 40-50g.
Osmanthus fragrans fingerlings with the size of 2.5-3.5cm are cultivated to 10- 12cm, the cultivation density is 6000-8000/mu, and the cultivation time is 25-30 days.
2.5-3.5cm to 40-50g, with a culture density of 4000-5000 fish/mu and a culture time of 40-50 days.
Technical points:
① Cultivate enough palatable bait fish before osmanthus seedlings go down to the pond, and strictly disinfect and kill insects in the pond water and bait fish. Insecticides should be carried out 1-2 days before stocking osmanthus fragrans, and ginger+fiber should be sprinkled 1 mu in advance or on the day of sowing to disinfect and kill insects and reduce stress reaction.
② Timely supplement palatable feed fish. The size of feed fish should be small under the premise of palatability, and it is appropriate to eat it in about 5 days at a time. Feed fish must be disinfected and killed by drug immersion bath before each feeding.
(3) When the cultivation standard reaches the predetermined specification, fish in the pond in the morning in cool weather.
(4) The fish species passed the tang qian sorting specifications, and the weak and deformed individuals were eliminated. The dosage of mould package and ginger sprinkling per set 1 mu can be used to reduce the complications of secondary infection.
3, fish stocking time
The stocking time of fish species affects the growth rate, feed coefficient (production cost), disease frequency and market price of osmanthus fish. Early or late stocking time is directly proportional to the growth rate and inversely proportional to the feed coefficient. Early sowing has a fast growth rate and a low feed coefficient. Usually, the growth rate of seeds released before May is particularly fast and the feed coefficient is low (between 3.5 and 4.5). After mid-July, the growth rate of released seeds is slow and the feed coefficient is high (5-8). The main reasons for this phenomenon are: (1) climatic and water temperature conditions; (2) Germplasm factors of seedlings.
Third, the reasonable stocking density of adult fish and the fish suitable for collocation feeding
The stocking density of osmanthus fragrans is very flexible, and the stocking density of adult osmanthus fragrans should be 1200- 1500 fish/mu (referring to the large-sized fish with standard thickness after cultivation, if the fish with specifications of 2.5-3.5cm are stocked, the stocking density should be increased by about 20%, that is,1500-/mu) The main cultured osmanthus fish in ponds should be equipped with bighead carp, crucian carp, etc., and the requirements for fish breeding are large, with bighead carp 200-500 g/tail and 20-30 tail/mu; Carassius auratus 40-50g/tail, 100- 150 tail/mu.
Four, feeding management technology
1, feeding technology
① Species of feed fish In order to make osmanthus fish eat balanced nutrition, a variety of feed fish should be fed. In Guangdong, Herring, Carassius mairei and Herring Rusta are all good feed fish, and silver carp, bighead carp, crucian carp and bighead carp are all suitable as feed fish for osmanthus fish.
② The specification of feed fish is based on palatability. On the premise of palatability, the specification should be slightly smaller but not larger, so that individuals of different sizes can eat, and the developed products have neat specifications and high commodity value.
(3) Feed the feed fish in time, and there shall be no disjointed feeding in the middle, otherwise diseases will be caused due to the impermanence of hunger, especially gastrointestinal diseases.
(4) Feed a small amount for many times, and it is generally appropriate to eat it in 5-7 days. In winter and early spring, the water temperature is low, and the intake of osmanthus fish is small, so it is appropriate to eat it in 7- 10 days each time.
⑤ Before feeding the feed fish, it is necessary to disinfect and kill the feed fish by drug immersion bath to prevent the pathogen from being brought in by the feed fish and cut off the transmission route of the pathogen. The disinfection and insecticidal methods of feed fish are as follows: using cellulose to kill 50ppm, soaking for 10- 15 minutes; Or soak in 3% ginger for 3-5 minutes.
Feed fish with diseases such as sporozoa, enteritis, hemorrhagic disease, etc. shall not be fed to osmanthus fish, and the feed fish purchased from abroad must be cautious to prevent disease infection caused by purchasing leftover feed fish from the diseased pond.
2. Water quality management Water quality management is one of the key technologies for raising osmanthus fish.
① The water quality of ponds for raising osmanthus fish is medium fat. The growth rate of lean water quality is slow and diseases are frequent. Overfertilized water is rich in organic matter and oxygen consumption factors, and the water quality is easy to deteriorate. The water with medium fertility has high plankton content, high oxygen production by photosynthesis and rich dissolved oxygen; When there are many microorganisms, the beneficial population often dominates, which inhibits the reproduction of diseased microorganisms, so there are few diseases. In addition, the water with medium fatness is not transparent, so it is suitable for osmanthus fish to inhabit and has a sense of security. Medium-fat water is specifically expressed by transparency, and the transparency is about 30cm, and the water quality is refreshing and oily green.
If the water quality is too fat, it is advisable to pump out some old water and replenish some new water. However, it is not advisable to change the water quantity too much at a time. Generally, the water level of about 30cm is appropriate. If the water quantity is too large at a time, the water environment in the pond will change sharply, which will cause stress reaction of osmanthus fish and cause diseases.
② Dissolved oxygen is the most important water quality factor, and ensuring the rich dissolved oxygen in pond water is an important water quality management content. Osmanthus fragrans is a benthic fish with high oxygen consumption rate and weak hypoxia tolerance, so it is necessary to use an aerator in the pond for raising Osmanthus fragrans. The standard for equipping the pond with an aerator is 0.4-0.5KW/ mu of impeller aerator. The dissolved oxygen in the pool should be kept above 4.5mg/L, and not less than 3mg/L at the lowest time. If it is less than 2mg/L, "floating head" will appear. Generally, the startup time is from around midnight to the next day after the sun comes out, and it starts at noon 10- 12 hours 1.5-2 hours. If the weather is bad, it should be started early and the startup time should be extended. Oxygen not only affects fish's breathing and life safety, but also affects fish's ingestion, digestion, absorption, growth and development, and other water quality factors. When the dissolved oxygen in water is rich, the fish eat a lot, the utilization rate of digestion and absorption is high, the growth rate is fast and the feed coefficient is low. In the case of rich oxygen, many harmful poisons are oxidized. For example, when dissolved oxygen is rich, hydrogen sulfide in water cannot be produced and accumulated. When dissolved oxygen is abundant, beneficial aerobic bacteria have strong reproductive ability, accelerate the decomposition of macromolecular organic substances and harmful poisons, and accelerate the material circulation ability of ponds, thus improving the productivity of fish ponds.
It is best to equip the osmanthus fish with a generator set and prepare some chemical oxidants, such as calcium peroxide [CaO2], sodium perborate [NabO3 4h2o] and sodium percarbonate [2naco3 3h2o2], for emergency use.
③ Elimination and control of harmful and toxic substances in pond water: Osmanthus fragrans has a high feeding density, large food intake and a lot of excrement. Especially in the middle and late feeding period, metabolic excrement is decomposed by bacteria to produce a large number of harmful and toxic substances such as nitrite [NO2- 1-N], ammonia nitrogen [NH3-N], methane [CH4] and hydrogen sulfide [H2S], and the organic oxygen consumption is also high, which affects the intake of Osmanthus fragrans. The red-billed ophthalmopathy induced by water quality deterioration is an obvious example.
Now microbial agents have been widely used to control and improve the water quality in ponds, such as noramin, algae species, nitrifying bacteria, photosynthetic bacteria, EM bacteria and so on. The so-called microbial preparation, also known as microecological preparation, is made by screening out some beneficial bacteria and artificially cultivating them. Microbial preparations are generally composed of a variety of bacteria, but there are also a single kind of bacteria. There are four main functions of microbial agents: first, microbial agents multiply in pond water and sediment after application, and inhibit the growth of disease microorganisms; Second, the bacteria in the microbial preparation decompose harmful toxic substances and macromolecular organic substances in the pond water and sediment, decompose harmful toxic substances into harmless non-toxic substances, and decompose macromolecular organic substances into small molecular inorganic nutrients to accelerate the material circulation in the pond; Third, photosynthetic bacteria, specifically photosynthetic pigments, can carry out photosynthesis under anaerobic and light conditions, and use solar energy to obtain energy, but do not produce oxygen. In aquaculture water, hydrogen sulfide or small molecular organic matter can be used as hydrogen donor, and at the same time, small molecular organic matter can be used as nitrogen source, and ammonia salt and amino acid can be used as nitrogen source, so harmful substances such as ammonia nitrogen, hydrogen sulfide and organic acid can be eliminated and oxygen consumption of water body can be reduced; Fourthly, mixing microbial preparation with feed, feeding or spraying it on the leaves of crops can promote the digestion and absorption of feed by raised animals and promote the growth of plants. Microbial preparations are usually applied once every half a month, and once a month in winter when the water temperature is low. Microbial preparations should not be used together with antibiotics and sterilization drugs, otherwise, the bacteria in microbial preparations will be killed and will not work.
Use drugs to adjust and control water quality. Noramin+algae seeds 3 mu/bag, applied in the morning, once every half month or so. Zeolite powder is 20-25kg/ mu, which is used to adsorb heavy metal ions and other harmful poisons. Polyaluminum chloride can also purify water, the dosage is 5-7kg/ mu. m, and it is splashed all over the pool after being stirred with water. Alum has the function of coagulation and precipitation, which can coagulate and precipitate dissolved and suspended organic and inorganic particles, make the water clear, eliminate ammonia nitrogen and nitrite, and reduce the pH value of the water. When the water quality of the source water is poor or the change of water may lead to disease and infection, it is very effective to implement closed culture without changing the pool water and adopt drugs to treat the water quality.
④ When the temperature is high in summer, raising the water level in the pond as much as possible can effectively reduce the occurrence of diseases; In winter, the water level in the pond should also be deepened appropriately to help osmanthus fish overwinter safely and prevent frostbite.