Crayfish like shade and are afraid of light. When the light is weak or dark, crayfish usually cling to aquatic plants or suspended solids in the water body and "sleep". When the light is strong, it will sink to the bottom of the water or hide in the cave.
Crayfish has a wide range of water requirements. It can survive in lakes, rivers, ponds, canals and paddy fields, and has strong pollution resistance, even in some water bodies where fish are difficult to survive. Many species of crayfish are of economic value and edible. Artificial farming has developed rapidly.