The sides are silvery blue-gray with an occasional pinkish cast and anterior dark spots. The lower sides have a dark stripe extending from the pectoral fin to the pelvic fin. The belly is grayish. The head is short with the mouth extending to the middle of the eyes. The jaw contains small teeth.
Fins are dusky to dark, the dorsal fin has a light margin.
There are seventeen to twenty-five rays, the adipose fin is present and the caudal fin is deeply forked. T. arcticus is an attractive and important sport fish in northern Canada and Alaska. Native Alaskans depend on it for a food source in remote areas. Various bottom substrates are used with fine gravel being the preferred. Between 4,000 and 7,000 eggs are laid and hatch between 11 and 18 days.