Fishermen in Ca Mau, Vietnam, captured a strange-looking crab that had a blue shell.

Footage from June 13 shows the filmer pull the blue-shelled crab out from a box of normal green crustaceans.

According to scientists, the crab's colour could be down to its diet or a mutation that causes a lack of pigment.

The crab was later released back into the sea.

Video captured the moment of Vietnamese fishermen caught a strange blue crab in Ca Mau, Viet Nam.
According to the fisherman, while he was fishing for crabs, he caught a strange crab. The blue crab weighs about 300 grams. It had a strange blue color different from the usual crabs he had ever caught. The whole body of the crab is covered with a green color from the body to the claws. This is the first time he has seen such a crab.
According to scientists, the reason why crabs have this color is due to the influence of diet or a mutation that causes a lack of pigment. "The crab's blue color could be the result of an extremely rare genetic mutation."
The crab was then released back to the sea by the fisherman.