Portunus sanguinolentus

The three-spot swimming crab (Portunus sanguinolentus), also known as the blood-spotted swimming crab or red-spotted swimming crab, is a large crab found throughout estuaries of the Indian and West Pacific Oceanic countries. A cosmopolitan species widely distributed all major water of the world, found through Red Sea, Persian Gulf, Mozambique, South Africa, Madagascar, Mauritius, Pakistan, India, Maldives, Sri Lanka, Andaman Islands, Myanmar, Malay Peninsula, Thailand, Japan, Korea, Taiwan, China, Singapore, Indonesia, Philippines, Java, Australia, and Hawaii. Two subspecies are recognized: A large crab with 15–20 cm of maximum length. Greyish green carapace is very broad and characterized by 3 red spots in posterior half. A strong spine can be seen on each side. Swimming legs are flattened and claws are long.