From fingerlings with a total length of 3-4 cm to commercial fish with a tail weight of more than 600g, 20,000-25,000 fish can be raised on an acre of effective water surface (except fish farming). When the red-eyed trout grows to 20/kg, 10/kg and 5/kg respectively, it can be sold in the catching pond, and finally it can stay in the pond for about 1800 ~ 2000/ mu to develop large-scale commercial fish with specifications above 600g g.

2. Feed nutrition index

Under the condition of pond culture, it is appropriate to feed artificial compound granular bait, and the animal protein content in compound feed at each stage should account for more than 1/3 of the total feed protein.

The nutritional index of each stage is: from summer flower to fingerling stage, the feeding time is100 ~10 day, and the crude protein content in the compound feed at this stage should reach 30 ~ 34%. The feeding time from fingerling to adult stage is 120 ~ 160 days. At present, the content of crude protein in compound feed should reach 28 ~ 32%.

3. Feeding methods of economic fish

1), stocking density in the main pond: on the premise that the pond meets the required conditions, the average stocking tail weight per mu of effective water surface is 40-60g, and there are1800-2,000 large fish, with a total length of 12cm, which can be matched with silver carp100 ~/kloc.

2) Domestication and feeding: Red-eyed trout is sensitive, easy to float, domesticated, likes floating materials, eats grass and is easy to raise. In aquaculture, the fish just put into the pond should not be busy feeding, because the fish just put into the pond have not adapted to the environment, the stress reaction has not been eliminated, and their physique has not recovered, so they will not eat immediately. After the fingerlings enter the pond, they should be allowed to stand for 2-3 days, and then they can be domesticated and fed after adapting to the environment.

Cultivation techniques of commercial adult red-eyed trout

The method is to set 4 ~ 5 feeding points around the pond, and then train and feed the fish by clapping or playing. At this time, fish are fed twice a day, once in the morning and once in the afternoon. After 3 ~ 4 days of domestication and feeding, most pond fish float up in groups, and when they come to the feeding point to grab food, they are transferred to the set food table for formal feeding.

3) Size of fish and food granularity: When the tail weight of fish is below 100g, crushed palatable particles should be fed. When the tail weight of fish reaches 100 ~ 300 g, artificial particles with the particle size of 1.0 ~ 1.5 mm should be fed to match the mouth shape. When the tail weight of fish reaches 300 ~ 600 g, artificial compound granular bait with particle diameter of 1.5 ~ 3.0 mm should be fed.

Because this fish is a herbivorous population. During the feeding process from fingerling to adult fish, some green feeds (such as duckweed, duckweed with purple back, black algae, ryegrass in the open field, vegetable leaves, tender grass, etc. ) Feed it properly. This can not only meet the nutritional needs of its growth stage, but also effectively reduce the feed cost (when feeding fresh grass in spring and early summer, it should be chopped before feeding, and in midsummer, it can be directly fed when the weight of fish tail grows to more than 150g).

4) Feeding time and feeding amount: When the water temperature reaches 10 degrees Celsius in spring, the fish have already started feeding. At this time, experimental feeding can be carried out in the pond in order to induce them to start eating early. This stage is a trial feeding and domestication feeding stage, which is fed once a day, that is, at 2 ~ 3 pm.

When the water temperature rises to 14 ~ 18 degrees Celsius, the daily feeding frequency should be changed to twice, that is,10 ~1,and 3 ~ 4 times in the afternoon. When the water temperature rises to 18 ~ 30℃, the feeding frequency is 3 times a day, that is, 7 ~ 8 am,112 pm and 4 ~ 5 pm. You can also feed granular bait once in the morning and evening and green feed once in the evening.

If there is no green feed, the time of feeding three times a day should be changed to 8 ~ 9 am, 1 1 ~ 12 pm and 4 ~ 5 pm.

In autumn, when the water temperature drops below 8 degrees Celsius, adult fish are basically in a state of not eating.

When the water temperature is 10 ~ 14 degrees Celsius in spring, the daily feeding amount of fish is 0.3 ~ 2% of the total weight of fish in the pond. When the water temperature rises to 14 ~ 18℃, the daily feeding amount is 2 ~ 5% of the total weight of fish in the pond. When the green feed is sufficient, the daily feeding amount is 8 ~ 13% of the total weight of fish. While feeding green feed, the artificial pellet feed decreased by 8 ~ 65433.

When the pond fish are tamed to float, flock and grab bait, they should be immediately transferred to the bait table set in advance for centralized feeding. In the feeding technology, we should adopt the feeding methods from slow to fast, from fast to slow, from less to more, from more to less. We should spread the bait on a large and uniform surface, and it is best to feed the bait from fish to adult fish on time with a bait machine.

5) Raw materials and quality: The main feed raw materials are fish meal, soybean meal, rapeseed meal, peanut cake, bran, rice bran, secondary meal, other minerals and trace elements. However, its raw materials must be fresh, non-corrosive and pollution-free, and it is forbidden to use deteriorated raw materials. It is also required that the protein content in the compound feed for red-eyed trout should be kept at 30-32% in the juvenile stage and 28-30% in the adult stage, and the fed green feed should be free from pesticide residue, aging, rot and mildew, so as to ensure the freshness and avoid fish poisoning or disease in the pond.

6) Water quality adjustment: The anoxia tolerance of this fish is slightly worse than that of other conventional fish during the feeding stage from fingerling to adult fish, so the water quality and water level of the culture pond should be carefully adjusted.

In general, fresh water should be added every 10 ~15 days from the time when the water temperature reaches above10℃ after the first water injection before fish stocking, and the amount of water added each time should not be less than 10 ~ 15 cm. With the increase of double temperature, the water level in the pool will gradually increase.

With the growth of fish and the increase of food intake, the substances excreted in pond water increase relatively. In addition, some humic substances need oxygen to decompose and transform, which increases the oxygen consumption coefficient. Therefore, the management of pond water quality should be monitored and adjusted according to weather conditions and water quality changes.

It is necessary to replenish fresh water in time to keep the water quality of the aquaculture pond good for a long time. The dissolved oxygen must reach above 4 mg/L, and part of the old water in the pond should be removed to replenish enough new water. During the breeding period, keep the water quality of the breeding pond tender, lively, fat and cool.

4. Feed feeding

The crude protein content of artificial compound feed for adult red-eyed trout should be about 28 ~ 30%, and the feed coefficient should be about 1.8. The raw materials of compound feed should meet the requirements, and raw materials that are damp, moldy, moth-eaten, spoiled and contaminated by oils, pesticides and harmful metals shall not be used.

Feeding should follow the scientific principle of four observations and four determinations, and master the feeding amount flexibly every time. Feed 1 time every morning and evening in the main growth period, and it is generally appropriate to eat it about 20 ~ 30 minutes after feeding. In addition, according to the feeding habits of red-eyed trout, some green feed, such as duckweed and other aquatic plants and grasses, should be fed to promote its growth, reduce feed cost and improve economic benefits.