Commercial adult fish culture techniques of red-eyed trout

Stocking density of commercial fish culture ponds

From the breeding of full-length 3~4cm to the commercial fish with tail weight more than 600g, 2 ~ 25000 fish can be stocked on the effective water surface per mu (except fish culture). The red-eye trout can be sold on the market when the red-eye trout grows to 20 / jin, 10 / jin and 5 / jin, respectively. finally, about 1800 to 2000 red-eye trout / mu can be developed into large commercial fish of more than 600g.

Nutritional index of feed

Under the condition of pond culture, artificial pellet feed should be fed mainly, and the animal protein content in the formula feed should account for more than 1 to 3 of the total feed protein in each stage.

The nutrition indexes of each stage are as follows: from summer flower to fish fingerling stage, the feeding time is 100-110 days, the crude protein content in formula feed should reach 30-34%; from fish fingerling to adult fish, the feeding time is 120-160 days, and the crude protein content in compound feed at this stage should reach 28-32%.

Breeding methods of commercial fish

The main results are as follows: 1. The stocking density of the main culture pond: under the premise that the pond meets the requirements, the average weight of the tail on the effective water surface per mu can be 40060g, the total length is more than 1800002000, and it can be matched with 100,130 silver carp, 30 silver carp and 100 crucian carp of the same age.

2. Domestication and feeding: red-eyed trout has high sensitivity, easy to float, listening to domestication, fond of floating food, herbivorous and easy to raise. In raising, do not be busy feeding the fish that have just been put into the pond, because the fish that have just been put into the pond have not adapted to the environment because of the shock and discomfort in the process of transferring to the pond or transportation from other places, and the stress reaction has not been eliminated and their physique has not been recovered. It won't eat immediately. After entering the pond, the fish have to sit for 2-3 days and adapt to the environment, and then start domestication and feeding. The method is to set up 4-5 feeding points around the pond, and then train and bait the fish after applause or playing, and then feed them twice a day, once in the morning and once in the afternoon. After 3-4 days of domestication and feeding, most of the pond fish can float in groups, and when they come to the feeding point to grab food, they are transferred to the table that has been set up for formal feeding.

3. Fish body size and feed size: when the fish body tail weight is less than 100g, the crushed palatable particles should be fed; when the fish body tail weight is up to 100g and 300g, for the mouth shape, the artificial particles with the feed particle diameter of 1.0~1.5mm should be used. When the tail weight of the fish reaches 300 to 600g, the artificial compound pellet feed with the diameter of 1.5~3.0mm should be used. Because the fish is a herbivorous population. In the process of raising fish from fingerling to adult fish, some green fodder (such as duckweed, duckweed, verticillium verticillata, exposed ryegrass, vegetable leaves and tender grass, etc.) should be fed appropriately. This can not only meet the nutritional needs of its growth stage, but also effectively reduce the feed cost (when fresh and tender grass is fed in spring and early summer, it should be chopped and then fed, and in the middle of summer, the fish can be fed directly when the tail weight is more than 150g).

4. Feeding time and feeding amount: when the water temperature in spring is more than 10 ℃, the fish has already begun to look for food, and at this time, it can be fed into the pond in order to induce it to start feeding earlier. This stage is the trial feeding and training feeding stage, which is fed once a day, that is, from 2pm to 3pm.

When the water temperature rises to 14: 18 ℃, the daily feeding times should be changed to 2 times, that is, 10: 11 a.m. and 3: 4 p.m., and when the water temperature rises to 18: 30 ℃, the daily feeding times should be 3 times, that is, 7: 8 a.m., 11: 12 p.m. and 4: 5 p.m., it can also be changed to pellet feed once in the morning and afternoon, and one green feed in the evening.

If there is no green feed, the daily feeding time should be changed to 8: 9 a.m., 11: 12 p.m. and 4: 5 p.m.

In the autumn, when the water temperature drops below 8 ℃, the adult fish is basically in a state of no food.

When the water temperature of the fish is 10: 14 ℃ in spring, the daily feeding amount is 0.3% of the total body weight of the pond fish; when the water temperature rises to 14: 18 ℃, the daily feeding amount is 2% of the total body weight of the pond fish; when the source feed is sufficient, the daily feeding amount of the green feed is 813% of the total body weight of the fish.

When training the pond fish to float, cluster and grab the bait, it should be immediately transferred to the pre-set bait table to carry out centralized feeding. In the feeding technology, we should adopt the feeding method from slow to fast, from fast to slow, from less to more, and from more to less, and the bait should be sprinkled with large and uniform surface, and it is best to feed the fish to the adult fish on time with the bait machine.

5. Raw materials and quality: the main sources of feed raw materials are fish meal, soybean meal, rapeseed meal, peanut cake, wheat bran, rice bran, secondary powder and other minerals and trace elements. However, the raw materials must be fresh, non-rotten and pollution-free, the use of deteriorating raw materials is strictly prohibited, and the protein content of red-eyed trout in the formula feed for young fish should be kept at 3032% and at the adult stage at 280.30%. The green feed should be free of pesticide residues, non-aging, non-decay, no mildew, to ensure freshness, and to avoid poisoning or disease of pond fish.

6. water quality regulation: the hypoxia tolerance of this fish is slightly worse than that of other conventional fish in the feeding stage from fingerling to adult fish, and the water quality and water level of the culture pond should be carefully adjusted.

From the completion of the first water injection before the release of the fish, and when the water temperature is more than 10 ℃, the bait is counted, usually, every 10-15 days, the amount of new water injected can not be less than 10~15cm, with the increase of the double temperature, the water level of the pool should be gradually increased, especially in the midsummer period to control the water level above the highest point of 2.5m.

With the growth of fish, the food intake increases, the excretion of substances in the pond water relatively increases, and some decaying substances need to be decomposed and transformed by oxygen, which increases the factor of oxygen consumption. Therefore, the management of pond water quality should be based on weather conditions and water quality changes. Timely do a good job in pond water quality monitoring and regulation.

Timely injection of new water, so that the culture pond water quality is good for a long time, dissolved oxygen must reach more than 4mg/L; remove part of the old water in the pond, add enough new water. Keep the water quality of the breeding pond tender, live, fat and cool during the culture period.

Feed feeding

The crude protein content of the artificial formula feed for adult red-eyed trout should be about 2830%, and the feed coefficient should be about 1.8, which requires that the raw materials of the formula feed comply with the regulations. Raw materials that are affected by moisture, mildew, worms, spoilage and contaminated by oil, pesticides, harmful metals and so on shall not be used.

Feeding should follow the scientific principles of "four looks" and "four determinations", and flexibly control the amount of feeding each time. In the main growing season, it should be fed once a day in the morning and once in the afternoon, and it is appropriate to eat it in about 20-30 minutes after each feeding. In addition, according to the feeding habits of red-eyed trout, we should also feed some green fodder, such as duckweed and grass, so as to promote its growth, reduce feed costs and improve economic benefits.

Disease prevention and cure

Red-eyed trout is a species with strong disease resistance in freshwater farmed fish, which rarely occurs from fry (splash) to adult fish. However, under the condition of intensive culture in pond water, due to many factors, such as high stocking density, incomplete water use and imperfect management skills, it is inevitable that some common diseases occur occasionally, such as parasitic ring worms, rotifers, third-generation worms, anchor fleas, and bacterial diseases such as rotten gills and enteritis in the water environment with extremely poor water quality.

In the whole process of feeding, we should adhere to the principle of "prevention first, prevention is more important than cure", and earnestly do the following work in the prevention and treatment of diseases:

Thoroughly clean the pond and disinfect the fish; do not feed spoiled or moldy bait or unclean green fodder; timely injection or replacement of new water, in high temperature season to increase the storage capacity of pond water

Disinfect the water body in the season when fish disease is prone to occur, use quicklime according to mu effective water surface 10~12kg every 15 to 20 days, or use bleach (chlorine content more than 30%) 0.8~1.0ppm plus appropriate amount of water to thoroughly dissolve into slurry or liquid to sprinkle on the whole pool.

Keep the water clean, maintain the environmental hygiene of the pond, clean up the residual bait on the table in time, remove the dirt from the pond, get rid of the weeds on the edge of the pond, and ensure the environmental hygiene of the pond.

Adhere to patrolling ponds, symptomatic medication, fish medication, careful medication, red-eyed trout is very sensitive to copper sulfate, the main culture pond forbids copper sulfate, other drugs are roughly the same as conventional fish. The more commonly used and safe drugs are: quicklime, bleach, trichlorfon, oxytetracycline, dipterex, povidone iodine and so on.

Daily management

In the main growing season, persist in patrolling the pond every morning and evening, carefully observe the fish activity, food intake and water quality, and make a good record of Tangkou. In the high temperature season, we should pay attention to timely change of water, generally about 10 days to add a change of water, in order to maintain fresh water quality and high dissolved oxygen content.

Turn on the aerator from 1 pm to 3 pm every day during the growing season, and turn on the aerator in time once a floating head is found. Every 20 days or so, every cubic meter of water is dissolved with 20g quicklime and sprinkled throughout the pool to regulate the water quality.

The prevention of bacterial diseases can be sprinkled with germicidal disinfectant once a month (May-September). Parasitic diseases can be sprinkled with avermectin in the whole pool. If you have Anchor head disease, you should sprinkle it again every 5 to 7 days. Before the adult red-eyed trout is on the market, the drug should be stopped in accordance with the corresponding drug withdrawal period, so as to ensure the quality of the listed fish.

Matters needing attention

Cage culture of red-eyed trout commercial fish needs to be covered with a net, because the fish likes to jump; the fry in the pond need to increase the stocking density, 2.5 ~ 30000 fish per mu can be released, and then the commercial fish are cultured in separate ponds when the specification grows to about 60 to 70; when feeding in the pond intensive culture process, the start-up time is about 10 minutes, and it is better to start again after a few minutes.