Culture method of platypus fish

1. Fish fry rearing 

The method of raising seedlings in flume is generally adopted. After coming out of the film, it is cultivated in the flume for 30-40 days, until 3-5 cm into the pond, this process is the key to the survival of fish fry. 

(1) the conditional area of the sink is about 10 square meters, either rectangular or circular, without sharp corners, convenient for entry and drainage, and equipped with escape prevention facilities. Good water quality, no pollution, toxicity, need to be filtered and used. Exchange water twice an hour (stop water for half an hour when feeding), water temperature between 16-28 ℃, dissolved oxygen more than 5 mg / L. 

(2) the stocking density of spoon-nosed Sturgeon fry decreased from 200 fish / square meter to 100 fish / square meter when it grew to 5 centimeters.

(3) the opening bait and feeding spoon snout Sturgeon are zooplankton, and the egg yolk can also be used with zooplankton. The best opening bait of spoon-nosed Sturgeon is copepod Cyclops. If you feed Cyclops, you must grasp the release time, so as to prevent Cyclops from breaking the yolk sac of fish fry and causing mass death of fish fry. The appropriate daily feeding times is 4-8 times, and the breeding room should also be fed at night, and the quantity should be slightly surplus. The initial feed should pass through the 60-mesh sieve to screen out large individuals and harmful aquatic insects. In the later stage, the artificial compound food can be eaten after domestication, and the food intake is about 30% of the body weight. Spoon-nosed Sturgeon has extremely poor eyesight and will not take the initiative to look for food. 

(4) daily management and matters needing attention should be discharged, screen windows should be washed, detailed records should be made, etc. When the fry grows to 3-5 cm, several abnormal conditions occur, such as gathering at the corner of the sink, fish fry biting and devouring each other, different sizes, and so on. The reasons for these conditions are uneven nutrition and excessive density. In addition, due to lack of nutrition, fish fry will also swallow water bubbles, making the digestive tract expand and bleed until death. 80% of fry deaths are caused by bite and phagocytosis, and about 20% are caused by gastrointestinal congestion. Therefore, fish fry after 3 cm and 5 cm should be put into ponds with balanced and adequate bait and large water body.

two。 Pond fish fingerling culture 

It takes 3 to 4 months for 3cm fry to grow up to 20cm in length and 200g in weight in that year.

(1) the pond requires a pond with a water surface of 3000mu, a water depth of 1.52m and convenient entry and drainage, and each pond should be equipped with a 1.5 kilowatt aerator. Before entering the pond, clean the pond with water, use 150 kilograms of quicklime per mu to kill miscellaneous fish, aquatic plants and so on. The temperature of the pool water is 2-37 ℃, and the optimum temperature is 25-32 ℃. 

(2) one week before the fertilizer and water goes into the pond, it is necessary to apply fertilizer to cultivate good water quality. the general fertilizers are manure (400,500kg / mu) and chicken and cow manure, and sprinkle soybean milk into the pond 3 days later, the dosage is 5kg / mu. Water spray net should be used to fish again before going into the pond to remove tadpoles and sundries. the difference between the water temperature in the pond and the fish container should not exceed ±3 ℃, and the operation should be carried out in the evening. 

(3) the main way of reasonable sparse culture is monoculture, with a small number of bottom fish and herbivorous fish, not with silver carp and ferocious fish. The stocking density should be 100 tails per mu. In the process of breeding, in addition to fertilizing and cultivating the water body, soybean milk (2 kg / mu), cake meal, floating wheat flour, bran or special pellet bait are also fed, which are always required to keep the water quality fertile, alive, tender and cool. 

(4) strengthen the management and persist in patrolling the ponds every day and make a good record of breeding. 

(5) Fish diseases and treatments above 10 cm and 15 cm are rarely fatal, but several cases of parasitic and bacterial diseases have been reported. Because the spoon-nosed Sturgeon is very sensitive to drugs, especially to heavy metal salts, it should be used with caution. Occasionally, fish diseases are mainly nematodes and trematodes, which can be treated with 2 × 10-6  potassium permanganate or less than 75 × 10-6  formalin. Copper sulfate and chlorine-containing drugs are prohibited in the stage of juvenile fish, and the immersion concentration of antibiotics is about 4 × 10 ~ 6. After cultivating a large fish species of 30cm to 40cm, it can be released directly into the reservoir, or it can continue to be cultured in the pond.

3. Release 

(1) the specification is 30mm, 40cm or more to ensure its viability and defend against other ferocious fish. 