(1) Natural bait All kinds of creatures that it likes to eat and naturally grow in water and land are called natural bait. There are mainly phytoplankton, aquatic plants, benthos and terrestrial plants.
Phytoplankton: including diatoms, Chrysophytes, dinoflagellates, gymnosperms, green algae, etc., which are the feed for early young crabs and zooplankton.
Zooplankton: rotifers, cladocera, cladocera, etc., are its good feed.
Aquatic plants: including Sophora alopecuroides, hydrilla verticillata, Potamogeton crispus, POTAMOGETON malayi, Spiraea japonica, Spiraea crassipes, Alternanthera philoxeroides, etc., are its main natural bait.
Benthic animals: snails, clams, mussels, water worms, etc. in waters are its best feed.
Terrestrial vivid plants: including Tenebrio molitor, earthworm, ryegrass, Pennisetum, comfrey, etc.
(2) Artificial feed Plant feed mainly includes soybean, bean cake, vegetable cake, cottonseed cake, wheat, rice bran, bean dregs, distiller's grains, sauce dregs and peanut cakes. Animal feed mainly includes snails, clams, mussels, silkworm chrysalis, Tenebrio molitor, earthworms, small miscellaneous fish, fly maggots and internal organs of livestock and poultry.
When putting in feed, we must adhere to the principle of reasonable collocation of fine, green and coarse. Generally, the daily feeding amount is 5%-8% of the crab's weight. However, crabs have the habit of gluttony for animal feed, so it is difficult to change it into plant feed in a short time if animal feed is put in for a long time.
The feeding method is different from other aquatic animals, but basically it should be "four fixed" (timing, positioning, qualitative and quantitative).
Timing: The feeding intensity of crabs increases or decreases with the change of seasons and water temperature. In summer and autumn, when the water temperature rises above 15℃, the crab's feeding ability is enhanced, so it is fed once a day. When the water temperature drops below 15℃, the feeding ability of crabs decreases, and they can be fed once every other day or several days. Feeding time should be around the evening, because crabs are aquatic animals that lie in the daytime and come out at night.
Timely prevention and treatment of diseases: In high temperature season, river crabs are prone to sudden onset, so we must adhere to the principle that prevention is more important than cure, supplemented by drugs to prevent diseases. You can sprinkle 1 mg/L oxytetracycline powder, 0.5~ 1 mg/L furazolidone, 1~2 mg/L zinc sulfate, 05 mg/L Xieanling and other drugs alternately on a regular basis; Feed medicinal bait frequently, and reuse 0.1~ 0.2g oxytetracycline or erythromycin for every1000g crab. Appropriate amount of shell powder, bone powder, fish powder and poultry eggshell powder are added to the feed to facilitate the shelling of river crabs. Parasitic diseases can be sprayed with 5~ 10 mg/l formalin or other pesticides in the whole pool, bacterial diseases can be disinfected with disinfectant for 2~3 times, and the effect is better if the whole pool is combined with feeding bait.
Prevent the loss of escaping crabs: crabs are most likely to escape in summer, frost and early autumn. Always check the escape prevention facilities, observe whether there are any signs of escaping, check whether there are holes connected with the external rivers and paddy fields, and solve problems in time. Check the retaining equipment at the outlet to prevent problems before they happen.
The daily management work is mainly to control water quality and disinfect regularly. Mix water with 5ppm lime emulsion every week and sprinkle it evenly in the whole pool, supplement some calcium and keep the pH value at 7.5 ~ 8.5; Disinfect with 0.5ppm of 50% stable chlorine dioxide every 1 0 day/time, and change water every 1 time every 15 day, the water change amount is about 30%, and some new water is added appropriately, and the water level is controlled at about 0.5m.. When changing water, the inlet and outlet should be wrapped with 80-mesh screen silk to avoid discharging seedlings or other harmful organisms. Pay attention to the temperature difference within 5℃, and the water temperature should be basically the same. Usually pay attention to the growth of aquatic plants in the pool and replenish some fresh aquatic plants in time.