The smallmouth flounder is a lefteyed flatfish, and is therefore very thin when lying on its side. Its mouth and eyeslie on the same side of its body, and are small compared to the rest of its head, and the lateral line has approximately 41 to 45 scales. The left pelvic fin lies below the lateral line, about one quarter down its body. The smallmouth flounder has 13rakers on its first gill arch. It is usually colored olive brownish with a white blind side, and it can grow up to 5 inches long.