日本蟳也称为赤甲红、花盖蟹。甲壳纲、十足目、蝤蛑科。具有大约12厘米（4.7英寸）宽的六边形凹面甲壳，整个动物呈淡绿色至橄榄绿色.日本蟳性凶好斗，常发生互相残杀，特别是在脱壳和交配期间。生活于潮间带至水深10-15m有水草、泥沙的水底或潜伏于石块下，属沿岸定居性种类。广泛分布于中国四海及日本、朝鲜、东南亚等沿海岛礁区及浅海水域。
学名：Charybdis japonica
英文名：Japenese stone crab
Charybdis japonica, the Asian paddle crab, is a species of swimming crab in the family Portunidae.Charybdis japonica has a hexagonal, concave carapace around 12 centimetres (4.7 inch) wide, the whole animal being pale green to olive green in colour.It’s violent and often kills each other, especially during the shelling and mating.It occurs naturally in the waters around Japan, Korea and Malaysia, it is also distributed in the four seas of China.