A kind fisherman accidentally caught a puffer fish in his line and released it back into the sea.

The trawlers were reeling in a catch a mile from the shore but found it was a poisonous puffer in Rayong province, Thailand, on September 15.

Footage shows the local using a knife to cut the cord around the marine animal's body. He was careful not to touch the spines of the deadly fish.

He then lifted a net and tossed it back into the water. The fish floated on the surface, still puffed up and in defence mode.

One of the fishermen onboard the boat, Monthon Niamchuen, said: 'We found the puffer fish and returned it to the sea.'

Pufferfish contains a potent toxin called tetrodotoxin, which is deadly if not properly managed. In Japan, there is a special culinary practice called 'fugu,' where licensed chefs prepare the fish in a way that ensures the toxin is removed or minimized.