The subject wants to ask, "Will crayfish die if they stay underwater for a long time?" No. Crawfish can be kept in deep water all the time. To ensure the range of crayfish activities, the landscaping in the tank should be as complicated as possible, and the water should be changed once every month on average/kloc-0, so that crayfish will not die. Crayfish is a general term for freshwater species of Decapoda. It is large, cylindrical, with a hard shell and a slightly flat head and breastplate. The front edge does not heal with the front plate of the mouth, and the side edge does not heal with the abdominal breastplate of the chest and the base of the chest limb, except for crayfish.