1. Pond conditions

The farm should be located in a place that is sheltered from the wind and sunny, with sufficient water, fresh water, no pollution, quiet and convenient transportation. The pond area is 3 mu to 5 mu, the water depth is 1.5 m to 2 m, and the thickness of the pond sediment is 20 cm to 30 cm. Each pond is equipped with 1 impeller aerator with power of 1.5 kW.

2. Clean the pond and fertilize it

Clean and disinfect the pond before releasing fish. Generally, in the first ten days of April, the pond is cleaned with 75 kg ~ 100 kg of quicklime per mu. After 7 days, water is added to the depth of 1 m, and then 300 kg ~ 400 kg of decomposed manure is applied per mu, and a small amount of green duckweed or red duckweed can be added.

3. Fish stocking

Every spring, when the water temperature rises and stabilizes above 15℃, winter seedlings are stocked. Generally, pond owners raise 1500 ~ 3000 fish per mu, and 40 ~ 70 silver carp and bighead carp are mixed to control water quality. When mixed with other fish, 200 ~ 500 fish can be raised per mu.

Step 4 feed the bait

Tilapia can be fed 2-3 days after entering the aquaculture water surface. Tilapia has a wide range of food habits. In the case of artificial feeding, it can be fed with various feeds, such as wheat, corn and cake, which are all high-quality feeds. The content of protein in feed should be 32% ~ 35% at first, and the daily feeding amount should be 3% ~ 5% of the total weight of fish. When the individual size is about 200g, the feeding amount can be adjusted to 2% of the total weight of the fish, and the protein content in the feed can be ensured to be 27% ~ 29%. When the individual reaches about 300g, the tilapia enters the fastest growth period, the daily feeding amount is kept at 65438+ 0% ~ 2% of the fish weight, and the protein content in the feed is above 35%. Feed twice a day at 8:00-9:00 am and 3:00-4:00 pm respectively.

5. Daily management should pay attention to patrol the pond day and night.

(1) Measure the water temperature and air temperature every morning, noon and evening, measure the pH value 1 time every week, and measure the transparency twice. Patrol the pond in the morning and evening 1 time.

(2) After the fingerlings enter the pond, the pond water should be kept dark brown with a transparency of 25cm ~ 30cm. Generally, the fertilizer is applied once a week 1 time, and the livestock manure per mu 150 kg ~ 200 kg each time. When the weather is clear and the water transparency is more than 30 cm, the amount of fertilization can be appropriately increased; When the water quality is too fat, we should reduce or stop fertilization and inject new water. In hot season, water is generally changed 1 ~ 2 times a week, and 20% ~ 30% of the pool water is changed each time.

(3) Adhere to healthy farming, standardize operations and prevent fish diseases. Soak the fish 10 minutes to 15 minutes with 5% salt solution or 0. 1 mg potassium permanganate solution per liter before the fry enter the pond. Every 65,438+00 days to 65,438+05 days, 65,438+05 kg ~ 20 kg of quicklime water per mu is sprinkled in the whole pond, the pH value of the pond water is adjusted to be slightly alkaline, and biological agents are used to improve the microbial structure of the pond and improve the water quality. When the dissolved oxygen is low and the fish has a slight floating head, turn on the aerator.

Second, paddy field culture.

Land of fish and rice, can double harvest. Attention should be paid to scientific feeding in interplanting tilapia in rice fields.

1. Stocking preparation

After the completion of the paddy field project, two weeks before stocking, 75 kg ~ 100 kg of quicklime water per mu was sprayed in the fish ditch and ridge for disinfection, and the bottom of the ditch and ridge was raked 1 time the next day, so that lime slurry and sludge were fully mixed. Before seedling release 1 week, fertilizer water from fermented animal manure was applied, with the dosage of 200 kg per mu, for cultivating natural bait in water.

2. Lead time

Generally, about 5 days after transplanting rice seedlings, the seedlings will be released when they turn green. In some places, in order to increase the growth period of fish, it is also an effective and good way to put fish in the fish ditch in mid-May and put them in the ground after the seedlings turn green.

3. Stocking method

Fish species should be selected with strong physique, strong activity, no damage and neat specifications. The stocking density should be reasonable. Generally, 200 ~ 300 tilapia fingerlings with specifications of 5 cm ~ 6 cm can be released per mu, with grass carp, carp and other fingerlings 150 ~ 200. The specific stocking amount can be flexibly mastered according to paddy field conditions, water quality environment, irrigation and drainage conditions and management level.

4. Inventory operation

Fish should be disinfected before entering the pond. Generally, fish should be soaked in 3% ~ 5% salt water for 5 minutes ~ 10 minute. Fish should be released in sunny morning or evening, but not in rainy day or sunny noon.

5. Feeding and fertilization

Generally speaking, Luo Fei, which is cultivated in rice fields, does not eat, and grows entirely by eating natural bait. However, the natural bait in rice field is limited, so it is suitable to feed some bait to accelerate its growth and improve its yield. Feed bait twice a day, and the feeding amount can be controlled within 2 hours after eating bait. There is no special requirement for applying base fertilizer and farmyard manure to fish-farming rice fields. Such as urea, ammonium sulfate, etc. They are all used as topdressing, and should be applied in small amounts several times, one and a half fields at a time. It is forbidden to apply fertilizer directly in the fish ditch.

Thirdly, cage culture.

Tilapia can be raised singly, mainly or together in cages. The species of fish should be of large size, and the size of the fish in the box is generally 10g ~ 50g. When the dissolved oxygen is above 3 mg per liter, the stocking density is 3 kg ~ 20 kg per cubic meter.

Fourth, flowing water culture.

Tilapia is one of the main objects of high-density or "factory" culture in running water at present. The aquaculture pond should not be too large, generally it is advisable to raise fish from 30 square meters to 50 square meters, and keep the dissolved oxygen in the pond above 3 mg per liter. Intensive farming needs to be fed with compound feed with comprehensive nutrition, and the protein content of the feed should be about 30%. Feed it 5 ~ 6 times a day, and the feeding amount is 2.5% ~ 3% of the fish weight.

Several key problems in tilapia culture

Among many tilapia seedlings, it is generally believed that the seedlings bred by interspecific hybridization of tilapia have the characteristics of fast growth, large size, good cold tolerance and high male rate, which is widely recognized by farmers. Its commodity names mainly include: Oni, Oza, Wu Guoyu, Androgyny, etc. At present, the quality of fry produced by different fry production units is quite different. Farmers should select a seedling with the fastest growth rate and the highest male plant rate from many varieties through breeding.

The parthenocarpy tilapia produced in China objectively did not reach the male rate of 100%. In the breeding production, there are more or less inferior offspring, which increases the breeding density, consumes a lot of feed, and even fails to meet the commodity specifications (its value is only about 20% of the normal product, so it is called cat fish), which seriously affects the output and benefit of tilapia breeding production. In order to solve this problem, there are the following measures:

1, and standard coarse matching and grading culture is implemented. Breeding producers should be equipped with enough standard thick ponds for secondary fry. The standard thickness of primary fry is about 20-50g, and that of secondary fry is about 200-400g. Then, the male fish will be sorted and put into the ponds to develop commercial fish. This can not only solve the problem of "cat fish" over-breeding, but also avoid the waste of water surface in the early stage of breeding.

2, artificial regularly eliminate inferior offspring. According to the characteristics of tilapia seedlings swimming in groups, in the breeding season, inferior seedlings are collected and removed from the pond every 2-3 days.

3, moderately stocking carnivorous fish. After the tilapia fry are stocked, some ferocious carnivorous fish such as Silurus meridionalis, barracuda and spotted snakehead (the stocking specifications are based on the tilapia that cannot be stocked) are appropriately stocked to prey on the offspring of tilapia culture. At present, farmers in Gaozhou generally mix 20 catfish per mu. If the pond is cleaned every crop, 20 spotted snakeheads, if the pond is not cleaned.

4. Batch culture and pool cleaning after harvest. Except the small reservoir in the mountain pond, it is really impossible to clean the pond with dry water. In general, the traditional way of catching and releasing is changed, and batch farming is carried out, and the pond is cleaned after harvest.

Due to the lack of funds and other reasons, many farmers first consider the price rather than the quality of feed when choosing feed. Choosing cheap and inferior feed will not only reduce feed cost, but also reduce production efficiency. Generally speaking, tilapia compound feed is required to ensure its crude protein content according to each growth stage, and the key is that it does not contain toxic and harmful substances. Otherwise, the normal growth of fish will be affected, and a large number of fish will die, resulting in reduced production. From the long-term practice of farmers in Gaozhou city, we know that the main influencing factors of feed on tilapia culture are: first, feed mildew, and second, compound feed contains more rapeseed cakes with toxins. Most of the dead fish in tilapia culture ponds in Gaozhou city are the above reasons. In particular, it is most common to produce a large number of dead fish by feeding feed containing about 20% rapeseed cake. Through the anatomical follow-up observation of these tilapia, with the increase of feeding time, the liver and gallbladder of the fish become larger and lighter in color. By the time of death, the liver turns pink, the gallbladder turns pale yellow and transparent, and the liver and gallbladder increase by 2-3 times. After the fish ponds with dead fish were switched to rapeseed cake-free feed and detoxification medicine feed, the phenomenon of dead fish gradually disappeared. We believe that rapeseed cake is highly toxic, and it has not been detoxified in production or the detoxification effect is not good, which leads to the toxicity accumulation of tilapia after eating. When the detoxification ability of liver and gallbladder reaches the limit, it will lead to the death of fish. Therefore, in tilapia production, we should pay attention to not using moldy feed and not using or using less compound feed containing rapeseed cake.

In order to make tilapia culture high-yield and efficient, in addition to stocking high-quality fish and feeding high-quality feed, it is necessary to let the fish have a good growth environment in order to make the fish grow normally and quickly. The key is to ensure the supply of dissolved oxygen in water. Excessive stocking density will lead to insufficient supply of dissolved oxygen in water and affect the normal feeding, digestion and absorption of fish. Therefore, the producer should set the stocking density according to the water capacity (pond depth), water supply, and whether or not an aerator is equipped. The stocking amount is generally controlled at about 1-2 fish per cubic meter of water. Farmers should grasp the best stock in production practice. When the fish reaches the production specification period, the feeding amount of about 2% of the body weight can be eaten under normal weather conditions.

Summary of experience in disease prevention and control of tilapia

In recent years, with the increase of export volume and the continuous improvement of people's quality of life, the quality and safety of aquatic products have been paid more and more attention, and the demand for pollution-free aquatic products has been increasing. Therefore, it is imperative to carry out standardized and healthy farming of tilapia, and one of the keys to standardized and healthy farming is disease prevention. The author summarized the experience of tilapia culture in Huazhou in recent years for reference.

The prevention of fish diseases is mainly based on prevention, which mainly adopts measures such as strictly controlling stocking density, adjusting aquaculture water quality, feeding fresh and comprehensive feed, and regularly sampling fish body surface and anatomical examination. Once fish diseases are found, aquatic professionals should be asked to diagnose them in time and prescribe the right medicine under the guidance of professionals. General measures are:

1, thoroughly clean and disinfect the pond; 2, fry, fish into Tang Qian strict disinfection; 3. After the fry and fingerlings enter the pond, spray 90% trichlorfon crystals of 1g/m3 once in the whole pond. Spray with 1-2g/m3 bleaching powder (28% available chlorine) once after half a month; 4. Keep the water quality fat, lively, tender, refreshing and slightly alkaline; 5. The dead fish should be fished out in time, disinfected and buried in the soil; 6. The equipment used in the sick fish pond shall be dipped and disinfected, and the water in the sick fish pond shall not be discharged at will without disinfection.

The use of fishery drugs must be strictly in accordance with the relevant provisions of the State Council and the Ministry of Agriculture. The usage and dosage of external drugs and oral drugs shall conform to the provisions of the aquatic industry standard "Guidelines for the Use of Fishery Drugs for Pollution-free Food (NY507 1-2002)".

See attached table for prevention and treatment methods of common fish diseases.