Scientific name: Thunnus maccoyii
The Southern bluefin, as its name would suggest, is found in the open waters of the Southern Hemisphere. One of the largest of the bony fishes, the Southern bluefin can reach 8.2 feet (2.5 meters) in length and 882 pounds (400 kg) in weight. They are a large, streamlined fish, and can swim very fast. Their bodies are completely covered in scales. They have blue-black backs and silver-white flanks and bellies. The largest bluefin ever recorded was a little longer than 12 feet (3.7 meters) and weighed more than 2,000 pounds (907 kg).