This is the heartwarming moment a pufferfish stuck on the muddy riverbanks was saved before dying of dehydration.

Sonsin Khaiochan was boating in the river when he found the helpless creature near a dam in Wang Sam Mo district, Udon Thani province, Thailand on November 1.

The pufferfish had already inflated when found, covered in brown mud that was starting to dry up.

At first, he thought the pufferfish was dead. The creature did not respond after being touched nor did it move when he carried it up.

But Sonsin's instinct told him he must let the creature back to the waters. The pufferfish remained still, even after being thrown into the dam, it floated back and forth.

He said: "Something told me it was alive, I stood on the boat hoping the fish would move after getting the taste of the water."

The merchant picked up the struggling marine animal and carefully threw it back into the water.

He went to pick it up again to clean up some of the mud off of it before returning it to the water again.

The tiny fish floated, as if it was dead. But its rescuer would not give up, Sonsin continued splashing water over the creature.

In the end, his faith saved the pufferfish. The creature deflated back to its normal size and swam away.

Sonsin added: ''It's only one small fish but I feel happy that I saved its life.''

Pufferfish can inflate their bodies whenever they feel threatened as soon as they hatch. This helps them appear more intimidating to potential predators.