Body Parts of Smallmouth Bass

Body Parts of Smallmouth Bass
Smallmouth bass are very similar to largemouth bass in terms of their physical anatomy, but their behavior tends to be very different. Smallmouth bass have different feeding preferences and have swimming and migratory patterns that are much more difficult to identify and chart. Smallmouth bass also have a different mouth structure than largemouth bass, which benefits them in different ways than largemouth benefit from their anatomy.

Mouth Structure

Despite their name, smallmouth bass actually have large mouths in proportion to their body; although, their mouths are smaller than the mouths on largemouth bass. Smallmouth bass, also called "smallies" by anglers, have mouths large enough to swallow prey whole, but this mouth is more heavily armored than largemouth bass. There are also more bones in the mouth to assist in consuming the type of food they tend to prefer, which, many times, is armored crustaceans, like crawfish.

Shape and Color

Smallmouth bass do not tend to be very big, with many falling between 2 to 6 pounds in weight. They are slender fish--much more so than largemouth bass--and are green to brown in color. Their scales feature vertical, colored bands that often appear bronze, and they have a white or cream underbelly.


Smallmouth bass have eight different fins: two pectoral fins, two pelvic fins, a spined dorsal fin, a soft dorsal fin, an anal fin and a tail fin. The pelvic fins are located directly below the pectoral fins, which are situated just behind the gill cover. The spined dorsal fin is located in the middle of the back and immediately in front of the soft dorsal fin. The anal fin is on the underside, almost identically corresponding to the soft dorsal fin. The tail fin is clubbed with sharp corners.


Smallmouth bass have very characteristic red eyes. For this reason, they can sometimes be confused with rock bass, which are a less common type of bass and tend to grow to larger sizes than smallies.

Nares and Gills

Nares appear on the front of the head, just above the mouth; however, nares have nothing to do with breathing--they are receptors that receive and process smells to enable the bass to hunt. The gills are located behind the eyes and just in front of the pectoral fins. They are hidden from view and protected by a gill hood, colored the same as the rest of the body's scales.

Article Written By Jonathan Croswell

Jonathan Croswell has spent more than five years writing and editing for a number of newspapers and online publications, including the "Omaha World-Herald" and "New York Newsday." Croswell received a Bachelor of Arts degree in English from the University of Nebraska and is currently pursuing a Master's of Health and Exercise Science at Portland State University.

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