How to prevent and cure three common diseases of river crab in summer peak growing season

The river crab grows vigorously in summer and enters the peak feeding period. the increase of feeding leads to the deterioration of water quality, and all kinds of pests and parasites take advantage of the opportunity to multiply, which makes the river crab poor resistance and easy to be infected with crab disease. So summer to prevent and cure river crab ciliosis, molting failure, edema disease.

river crab

Ciliosis: caused by parasites such as condensed worms, bell worms, cumulus and so on. The brown or light green floc grows on the body surface, appendages and gills of the river crab, which moves slowly, refuses to eat and dies with difficulty in molting. Crab ponds with high content of organic matter and no aquatic plants and climbing substances are prone to ciliosis. Prevention and control methods: ⑴ purchase of river crab species should pay attention to quarantine, crab species can only be released after disinfection. Improve the conditions of crab ponds, remove silt, plant aquatic plants, and adjust water quality. ⑵ sprinkled infected crab pond with formaldehyde or bromogeramine whole pond, the dosage was 40g ~ 50g and 20g ~ 30g per cubic meter of water respectively. ⑶ per cubic meter of water is sprinkled with 2 ~ 3 grams of zinc sulfate or 8 ~ 10 grams of bramycin in the whole pool.

Molting failure: sponges, ciliates parasitism, water pollution, no good concealment, climbing objects, malnutrition, crab body emaciation and so on will cause crab shelling failure. Disease, death and crab head chest shell warped or lacerations appear at the junction of the posterior edge and the abdomen. Prevention and control methods: ⑴ to optimize the environment of crab ponds, desilting and planting water plants, to maintain good water quality. A week before the moulting of a batch of river crabs, sprinkle the whole pool according to the proportion of 15 ~ 20 grams of quicklime per cubic meter to adjust the water quality. ⑵ is fed with palatable and nutritious feed, such as fresh mixed fish and clam meat, to ensure the success of crab molting for the first time. ⑶ was fed a diet supplemented with 2%-3% molting and multivitamins for 5 to 7 days.

Edema disease: mostly caused by bacteria and Mucor infection. The edema of river crab caused by bacteria is characterized by successively edema of hindgut and Gill, swelling of chest and abdomen, unable to crawl, and no change in shell color. The edema caused by Mucor is purely Gill infection, and the abdomen is not swollen but sunken inward because of emaciation. The lower part of the breastplate of the crab swells at the junction of the abdomen, but it is not transparent. The breastplate in the Gill area of the diseased crab is gray-white, moves slowly and dies on the shore. Prevention and treatment of bacterial edema: ⑴ continuously change water for 2 times, first discharge and then irrigation, 33% 50% of water each time. ⑵ every cubic meter of water is sprinkled with 1g ~ 2g bleach, or 1g oxytetracycline powder, or 15g ~ 20g quicklime in the whole pool. ⑶ per kilogram of river crab with 0.25g of oxytetracycline, 0.01g of dysentery, plus 0.5% 0.1% garlic bait continuously fed for 5 to 7 days. Prevention and treatment of edema caused by Mucor: ⑴ changed water for 2 times. ⑵ every cubic meter of water is sprinkled with 2 grams of bleach, or 10 milliliters of formalin, or 20 ~ 25 grams of quicklime.