The mottled sculpin is one of the most common freshwater sculpins. It's able to tolerate warmer water than the closely related slimy sculpin. Mottled sculpins can be found throughout the great lakes region and south to Georgia, plus in a wide area of the rocky mountains. Count the pelvic fin rays to distinguish this fish from a slimy sculpin: the slimy has 3 rays, the mottled 4.