dissostichus mawsoni Also known as the Antarctic Cod or Toothfish, this fish is the largest fish found in and around the Antarctic oceans. Adults can grow up to six feet and weigh in at 250 pounds. Additionally they are also able to survive at depths greater than 1000 meters deep. Like most Antarctic fish, the Toothfish has a number of special adaptations which make it more suitable for living in the frigid waters of Antarctica. Unlike other fish, the Toothfish doesn't use a swim bladder to maintain its position in the water column. In fact it lacks a swim bladder entirely. The Toothfish has a skeleton that has similar qualities to cartilage and extremely oily tissue. For these reason the Toothfish can maintain a near neutral state of buoyancy.