The fisherman caught a Warsaw Grouper weighing a whopping 350-pounds, according to the Florida Fish and Wildlife Conservation Commission.
The fish was caught with a hook and line in roughly 600-feet of water on December 29 off the coast of southwest Florida.
Biologists with the Florida Fish and Wildlife Conservation Commission estimate the fish is at least 50-years-old.
Making it the oldest sample they've ever collected for their program.
Warsaw groupers can grow to a length of 7.5 feet and weight of 580 pounds.
The record for the largest one caught in Florida is nearly 440 pounds.