Police said Mongkol Chaiyawan, 48, was hit by grenade shrapnel in his back and lungs.
He was rushed to Yala Hospital for an operation.
Mongkol’s friends told police that they caught the fish in Bae Moh village in Tambon Khao Toom in Yala’s Yarang district.
They lit a fire near a tree and an explosion occurred.
Police said they found shrapnel from an M26 grenade and believed it was hidden rather than intended to be used as an improvised bomb.
