Hemitripterus americanus are variable in color from blood red to reddish purple to yellow brown. The ventral surface is typically yellow. They have large heads and a robust, tapering body. There are obvious fleshy folds on the head and lower jaw. There is also an unusual ragged layer of skin on the first dorsal fin. They have large, fan-shaped pectoral fins and a small caudal fin. They have a broad mouth which is lined with several rows of teeth. The maximum published total length is and the maximum published weight is.
Hemitripterus americanus is considered to be a voracious predator which preys on a wide variety of animals including benthic invertebrates and fish such as herring, sand lance and silver hake. When they are removed from the water they inflate and if returned to it they cannot submerge. Spawning adults attach their eggs to the bases of sponges. Sea ravens produce antifreeze proteins found in their blood that allow them to survive in subzero temperatures.