Thanks to fishing guide Kirk Kirkland, they caught a record-breaking alligator gar in the Sam Rayburn Reservoir. The alligator gar is the largest freshwater fish in Texas. The species can live for more than 50 years and can close to 300 pounds. For about 70 years, the largest International Game Fish Association (IGFA) catch on record was a 279-pounder they landed in 1951; now, the record is a 283-pounder.