Wild crayfish cannot be eaten. The food and drug supervision department reminded that crayfish should be cleaned before cooking and thoroughly cooked during cooking. Do not process dead, sensory abnormal or stale crayfish; Don't eat the head and viscera of crayfish. It is recommended that crayfish eat farmed and try not to eat wild ones. From the environmental point of view, wild crayfish will absorb many pollutants during their growth, especially heavy metals, industrial wastewater and agricultural sewage. The water quality of cultured crayfish can be controlled. Crayfish need to grow in aquatic plants. If aquatic plants are planted well, crayfish can be cultured without antibiotics and rarely use drugs. After cooking, normal crayfish are red or crimson. If there are black spots on crayfish, it means that crayfish has been polluted or encountered harmful substances during its growth, so it is best not to eat them.