A fisherman was baffled when he reeled in a mutant swamp fish in southern Thailand.

The angler, Winit Pokting, was fishing in a canal near his home in Satun province near the Malaysia border when he pulled the bizarre pinkish-red creature out of the water on May 11.

The strange, elongated animal had a flesh-coloured body, small, beady eyes, and a gaping maw that held glassy rows of teeth. It had a dorsal fin along its back and deep-pink pectoral and pelvic fins.

Winit said he had caught the creature during low tide and has been keeping it in a tub at his home.

He said: 'It was my first time seeing a fish like it. I asked around, and no one knew what it was. I thought it was an eel at first, but normal eels don't look like it at all.'

Thanompong Buabanjong, an expert from the Satun Coastal Fisheries Research and Development Center, identified the fish as a bearded worm goby - a type of fish typically found in muddy mangroves or estuaries.

They are a burrowing species, often staying in riverbed holes during the day and emerging to feed at night.

Thanompong said: 'They are rarely seen because they tend to avoid villagers' boats and fishing lines. Their appearance probably means the mangrove forests in the area are healthy and abundant in resources.'

The bearded worm goby is a species of worm goby native to the Indo-Pacific region. They are commonly found in estuaries and coastal waters, and are sometimes eaten as a delicacy in Thailand.