Breeding techniques of mandarin fish fry

Mandarin fish fingerling cultivation is the basis of mandarin fish culture, mandarin fish fry cultivation can not be like other freshwater fish in the pond directly fed commercial feed or with fertilizer method and other cultivation, therefore, mandarin fish fry cultivation technology is directly related to the efficiency of mandarin fish culture, let's take a look at mandarin fish fry cultivation technology!

Culture conditions of mandarin fish fry

1. Environmental requirements: the pond requires a sandy bottom, less silt, an area of 2 to 3 mu, a water depth of more than 1.5 meters, convenient drainage and irrigation, light water quality, no turbidity, no sewage inflow, and a small amount of submerged water grass. The newly opened ponds depend on the quality of the soil. Acid ponds and ponds where the water is easy to get muddy are not suitable for raising mandarin fish.

2. Pond cleaning and disinfection: clear the pond with quicklime on April 5, pile grass fertilizer in the four corners of the pond around April 10, (if the bottom of the pond is fatter, but do not apply fertilizer) and add 0.8-1.0 meters of fresh water to cultivate water quality to cultivate natural bait for fodder fish.

3. Bait cultivation: the fish nest with crucian carp eggs (floating) is put into the pond for hatching. The density of fish fry is generally controlled at about 500000 per mu, and the fish eggs can be put in 2-3 batches with an interval of one day. In this way, the mandarin fry with uneven specifications can have palatable bait.

Cultivation mode of mandarin fish fry

The newly hatched fry are soft and delicate, smaller than domestic fish, and only about 4 mm long. After 50-60 hours of cultivation, the body length reached 4-5 mm, and the average number of heartbeats was 3 times per second. At this time, the mandarin fry began to feed, that is, it entered the summer flower cultivation stage. Since the 1990s, the cultivation techniques of mandarin fry have been continuously improved and improved. There are also a variety of cultivation methods, which are summarized as running water and still water cultivation in production. The survival rate of running water breeding is higher than that of still water breeding. But the growth rate is slightly slower than that in still water.

The main results are as follows: 1. Running water cultivation: running water seedling cultivation is divided into two ways: incubator and loop breeding, and the operation is basically the same.

① cultivation conditions: the incubator (ring) has the advantages of fresh water quality, large water exchange capacity, water temperature balance, small temperature difference and rich dissolved oxygen, which meets the environmental requirements for the growth of mandarin fry. This method is mostly used in production, and the mandarin fry that hatch the film in the incubator (ring) will continue to be nurtured in the original tank (ring) that controls the flow of water manually.

② stocking density: at the initial stage of breeding, the stocking density of mandarin fry is generally 5000 ~ 10 000 pieces per square meter, which decreases gradually with the increase of mandarin fish individuals.

③ cultivation method: in the process of mandarin fry cultivation, the hatchery tank (ring road) should be changed every 5 days or so, and the sediments on both sides of the bottom of the hatchery tank (ring road) should be removed. Siniperca chuatsi fry are gluttonous, and it is best to stop feeding fish a few hours before the hatchery tank (loop) turns to the loop, so as to avoid unnecessary loss caused by overeating.

2. Still water breeding: still water breeding is cultivated in fish ponds, cement ponds and cages.

① cultivation conditions: the ponds for cultivating mandarin fish fry are generally cement ponds, with an area of 30 square meters and a water depth of 0.8 square meters. Artificial reefs simulating natural waters can be set up at the bottom of the pond to create a good predation environment for mandarin fish fry.

② disinfection and stocking: before fry stocking, the breeding pond must be thoroughly cleaned and sterilized. The stocking density is generally about 7000 mandarin fry per cubic meter of water. When mandarin fish grow about 1.5cm, the effect will be better.

Feed mandarin fish fry

Mandarin fish is a typical carnivorous fish. it eats live fry and eats each other when hungry, which is determined by its biological characteristics. Accurate control of the feeding time of mandarin fry, selection of bait fish and timely supply of palatable food is one of the key measures for the success or failure of mandarin fry cultivation.

1. Feeding time: the organ differentiation and development of mandarin fry is closely related to water temperature. In general, the interval between fertilized egg and mandarin fry feeding is 112 / 120 hours, 105 / 115 hours and 90 / 98 hours when water temperature is 23.5 / 25 ℃, 24 / 29 ℃ and 26 / 29 ℃, respectively. At this time, mandarin fry move actively and can take the initiative to feed.

2. Open bait: whether the size of open bait fry is suitable or not directly affects the feeding and survival rate of mandarin fish fry.

① opening bait selection: in production, it is appropriate to choose snout snout bream, bream, mackerel and other fry with weak swimming ability as opening bait, especially the live fry just off the membrane for 8 hours, when the bait fish is easy to be swallowed by the whole mandarin tail.

② forbids feeding Laokou fry: if you feed Laokou fry, mandarin fry can only use a small part of the bait fish tail, and the rest is often hung on the mouth of mandarin fry, which not only affects movement, but also is easy to rot and decompose in the water, worsen water quality, and even break out fish disease.

③ feed on time: if you can't get palatable bait fish within 3 to 5 days after the mandarin seedlings start eating, then the activity ability suddenly decreases, and the sensation is dull, so you gradually lose weight and die, and even eat each other, and get stuck because you can't swallow.

3. Food production: the mouth crack of mandarin fish and the body height of bait fish constantly change with the growth. Mandarin fish in different periods need to be fed with feed fry at a certain stage of development before they can be swallowed by mandarin fish.

The 60-year-old mandarin fry of ① can only swallow the fine-scale oblique jaw fish fry of 60-216-year-old.

② 84-year-old Siniperca chuatsi fry can swallow 60-year-old and 216-year-old fish fry.

③ 108-year-old mandarin fish fry can swallow all stages before 216s and grass carp fry at 36th and 108th years old.

④ 144-year-old mandarin fish can swallow 36-108-year-old grass carp fry.

⑤ 144-year-old mandarin fish can swallow silver carp, bream bream, grass carp, Feng carp, common carp, silver carp and bighead carp fry at the age of 216,216 and 24,108, respectively.

4. Quantity of bait

① feeding quantity of different days: the diets and palatable feed fish specifications of mandarin fry of different ages were different. At the initial stage of feeding, the diets of each mandarin fry were 2 to 3 and fed slowly, 4 to 5 at the age of 4 days, 12 at the age of 5 to 8 days, 16 at the age of 8 to 12 days, and 15 to 20 at the age of 14 to 15 days, and the eating rate increased with the growth of the fish.

② judges whether the food is sufficient: the full mandarin fry has a swollen abdomen and a prismatic shape, and the tail stalk is slightly arched. Under the condition of running water, the hungry mandarin fry lie still against the inner wall or drift with the water, and the hungry mandarin fry have a flat body and spread out in the loop to find food.

5. feeding method: in the process of summer flower cultivation of mandarin fish, it can be clearly seen that mandarin fish begin to swallow bait fish from the tail, often half of the fish is contained in the mouth, half of the fish is exposed outside the mouth, while eating, swimming and digesting, and finally spitting off the head of the fish, sometimes the head of the bait fish can be seen hanging on the thorns behind the Gill cover of the mandarin fish larvae, which is often mistaken for parasites. In this case, there is no need for drug treatment, and the fish's head will fall off naturally after a period of time.

6. Strengthen management: during the period of mandarin fry cultivation, fine management must be carried out, water bodies must be thoroughly disinfected, pathogens should not be brought into the breeding pond, water quality should be strictly controlled, pollution should be discharged in time, and bait fish should be propagated in time. Attention should be paid to link up with the needs of mandarin fry cultivation, bait fish must be strictly disinfected before feeding, and drugs must be regularly sprinkled into the breeding pond to prevent and cure fish diseases, so as to effectively improve the survival rate of mandarin fry.