How to Raise Rice Field Crabs? Detailed Explanation of Breeding Methods and Technical Key Points

Rice field crabs are just ordinary river crabs. Raising river crabs in rice fields is beneficial to the joint growth of rice seedlings and crabs. So how do you raise rice field crabs?

1. Growth habits of rice field crabs

Rice field crabs are arthropods of the crustacean class, also called crabs or hairy crabs. They often burrow on the muddy banks of rivers, lakes and marshes, and feed on fish, shrimp, animal carcasses and grains.

Rice field crabs like to live in burrows on the muddy banks or tidal flats of rivers and lakes. Under natural conditions they eat aquatic plants, humus and animal carcasses, and they also like to eat snails and mussels. Occasionally they also prey on small fish and shrimp, and when food is scarce they may even cannibalize one another, or even swallow the eggs they are carrying.

2. How do you raise rice field crabs?

First you need to breed juvenile crabs, then release the juvenile crab seedlings. Before release they must also be disinfected, and anti-escape measures must also be set up. When feeding bait, feed 4% of the juvenile crabs' weight, 2-3 times a day. During the rice field crab breeding process you must also pay attention to dredging and changing the water.

Among these, the anti-escape facilities for rice field crabs mostly use plastic film, though some use cement boards for anti-escape, depending on each situation.

3. Prevention and control of rice field crab diseases and pests

1. Black gill disease

The gills of diseased crabs become infected and change color. In mild cases part of the left and right gill filaments appear dark gray or black; in severe cases all the gill filaments turn black. Diseased crabs move slowly and have difficulty breathing, commonly known as sighing disease. This disease mostly occurs in the late stage of adult crab breeding, and deterioration of the water environment is the main trigger for this disease.

2. Shell rot disease

The tips of the walking legs of diseased crabs are damaged, forming black ulcers and rotting. Then white spots appear on each segment of the walking legs, the back shell and the thoracic plate, gradually turning into black ulcers. In severe cases the shell is eroded into holes, exposing muscle or membrane, leading to the death of the river crab. This disease is caused by infection of the wound at the tips of the river crab's walking legs.

Prevention methods:

(1) Thoroughly clear the pond with quicklime, keep the water clean, often add fresh water in summer, and keep 5—10 cm of mud at the bottom of the pond.

(2) In ponds showing signs of disease, splash quicklime mixed with water over the whole pond at 15—20 PPM.

Treatment method: Splash bleaching powder over the whole pond at 2 PPM, and add sulfa drugs to the feed, adding 0.1—0.2 g of medicine per kg of feed, feeding continuously for 3—5 days.

3. Water mold disease

Flocculent filaments grow on the body surface of diseased crabs, especially at wound sites. Diseased crabs move slowly and reduce feeding, the wounds do not heal, causing the tissue at the wound site to fester and spread, resulting in death. This disease is caused by injury to the river crab and mold invading the wound.

Prevention methods:

(1) Do not injure the crab's body during operations such as catching, transport and stocking.

(2) Increase the feeding of animal-based feed before mass molting.

Treatment methods:

(1) Splash malachite green over the whole pond at 0.25 PPM, and apply once again after 5 days.

(2) Soak diseased crabs in 3—5% salt water for 5 minutes, and apply 5% phosphorus to the affected area.