12-year-old Conor Smith wrestled with the whopping fish for half an hour before successfully reeling in the 13 stone 5oz tuna.
The fish is twice his size and the same length as he is tall.
Conor was on a fishing trip during a family holiday in Madeira last weekend, when he caught the fish which had to be transported on a fork lift truck. His catch is thought to be a new world record for a child.
Conor and his father Frank had already been out on two fishing trips during their holiday - with little success. But the day before flying home to Halesowen, they thought they'd give it one last go.
The family are waiting for official confirmation that the catch is a new junior record.