Though related to the lake trout, the siscowet looks quite different with its deep, stout body and small head. Its nickname, "fats," is no accident either - the body tissue of this fish may be as much as 80 percent fat, among the highest fat content of any known fish.

The Lake Superior population of siscowet plummeted after the Great Lakes invasion of sea lampreys, but now that lampreys are controlled, "fats" has been making a comeback, much to the delight of anglers. These long-lived fish may grow to more than 50 pounds and may reach 20 years in age.