The Asian paddle crab Charybdis japonica is a portunid (swimming) crab native to marine environments of Central and South East Asia. It may impact native esturine communities by competing for space and resources with native crabs.

Charybdis japonica (Milne Edwards, 1861) belongs to the genus Charybdis of the family Portunidae (Decapoda, Crustacea). It is a eurythermic and euryhaline marine crab and predominantly distributed in China, Japan, the Korean Peninsula, and Southeast Asian countries (Yu et al., 2004).

As an intertidal crustacean, the Charybdis japonica is a euryhaline marine crab and predominantly distributed in the China, Japan, the Korean Peninsula and Southeast Asia countries (Yu et al., 2004). This species can tolerate a wide range of salinity from 10‰ to 35‰, and its optimum survival salinity ranges from 15‰ to 27‰.