In Canada, several separate populations of channel darters live throughout the lower Great Lakes, from the Detroit River to Lake Erie, and in the tributaries of Lake Ontario and the St. Lawrence River. The channel darter mainly inhabits large clean streams and rivers with bottoms consisting of large rocks, fine gravel and sand. The darter likes enough water current to keep the gravel bottom free of silt. Riffle areas are preferred during spawning and summer feeding, and deeper, quieter backwaters during the winter. In Ontario, the darter's habitat consists of streams and lakes over wave-washed sand and gravel bottoms, and beaches with slow to sluggish currents.

A small elongated fish, the channel darter's sandy or olive colouring provides perfect camouflage with the sandy-bottomed rivers and lakes in which it lives. The darter has a whitish underbelly, brown speckles on its back, and between 10 and 15 dark cross-shaped markings on its sides. A male's body and fins darken during spawning, and his head may turn almost black.During spawning, male channel darters establish small territories-usually centred around one rock-which they defend vigorously against other males. Females move into a male's territory, burrow into the gravel behind the stone, and spawn. Females will spawn successively with many males, laying between four and ten eggs in each nest until up to 400 eggs are laid.