Crabs need to be raised in water. Feeding crabs in cool places such as bathtubs or wooden barrels generally requires putting a proper amount of water to ensure the humidity required by crabs. Probably not too much water will be put in, but it can't be too much, otherwise crabs are prone to lack of oxygen and will accelerate their death.

If crabs are not kept in water, they can generally live for about 2-3 days. However, due to the different quality and environmental temperature of crabs, how many days crabs can live after leaving water depends on the actual situation.

Crab is a crustacean, belonging to the mollusk class Decapoda. Its body is protected by a hard shell and it breathes through its gills. Taxonomically, it is the same kind of animal as shrimp, lobster and hermit crab.

Most kinds of crabs live in the ocean or offshore areas, and some live in fresh water or land. Common crabs are Portunus trituberculatus, Portunus trituberculatus, Eriocheir sinensis and Eriocheir sinensis (Eriocheir sinensis, Eriocheir sinensis and Eriocheir sinensis).