Gars are elongated, cylindrical fish with long snouts with numerous prominent teeth. The body is covered with hard, diamond-shaped scales. The spotted gar has many well-defined roundish black spots on top of the head and on the paired fins. Upperparts are brownish or olive, grading to white below, with well-defined roundish black spots on top of the head, snout, an all of the fins. This gar is most similar to the shortnose gar, but note the differences in lateral line and diagonal row scale counts below.
Similar species: Missouri has four species of gars.
The shortnose gar (L. platostomus) is most similar, but lacks has well-defined roundish black spots on the top of the head and paired fins; the scales in a diagonal row, from the scale at the front of the anal fin to the scale on the midline of the back (both included) usually number 20–23 (while the spotted numbers 17–20), and lateral line scales usually number 60–64 (the spotted numbers 54–58).
The longnose gar (L. osseus) has a relatively longer, narrower snout than all our other gars: the least width of the snout goes more than 10 times into its length, and the width of the upper jaw at the nostrils is less than the eye diameter.
The alligator gar (Atractosteus spatula) has a short, broad snout: the distance from the tip of its snout to the corner of the mouth is shorter than the rest of the head, and the least width of the snout goes only about 3–5 times into its length; also, it is a very large fish, commonly exceeding 3 feet in length and 8 pounds in weight.