The smallmouth bass is generally brown (seldom yellow) with red
eyes, and dark brown vertical bands, rather than a horizontal band
along the side. There are 13–15 soft rays in the dorsal fin. The
upper jaw of smallmouth bass extends to the middle of the eye.
Males are generally smaller than females. The males tend to range
around two pounds, while females can range from three to six pounds.
Their average sizes can differ, depending on where they are found;
those found in American waters tend to be larger due to the longer
summers, which allow them to eat and grow for a longer period of
Their habitat plays a significant role in their color, weight,
and shape. River water smallmouth that live among dark water tend to
be rather torpedo-shaped and very dark brown to be more efficient
for feeding. Lakeside smallmouth bass, however, that live in sandy
areas, tend to be a light yellow-brown to adapt to the environment
in a defensive state and are more oval-shaped.