Round Whitefish

Prosopium cylindraceum

The round whitefish (Prosopium cylindraceum) is a slender freshwater fish reaching up to 56 cm. It has a distinctive cylindrical body shape, small downward-pointing mouth, silvery sides, and a dark olive-brown back. Found across northern North America from Alaska and Canada to the northern United States, with an outlying population in New England, it inhabits cold, clear lakes and rivers at depths of 0 to 100 meters. This species feeds on benthic invertebrates including aquatic insects, snails, and clams, using its small mouth to pick prey from rocky and gravel substrates. It spawns in autumn over gravel shoals. Freshwater divers in northern lakes encounter these elegant fish gliding through crystal-clear water, where their silvery forms reflect light beautifully against dark lake bottoms.