Phenacobius catostomus, commonly known as the riffle minnow, is a North American species of cyprinid freshwater fish. It inhabits riffles in warm streams of medium to large size, in the states of Alabama, Georgia, and Tennessee, above the fall line. Long and slender, it averages about 3.5 inches (8.9 cm) in length. The riffle minnow is olive on top, and white below. This fish is not to be confused with Alburnoides bipunctatus, which is also known as riffle minnow, but lives in Europe and Asia.