[2] Fish of this species are usually deep-bodied, flattened sideways, and somewhat circular or rounded, with blunt noses and small mouths with weak teeth.

The American butterfish is similar in appearance to its close relative, the harvestfish (Peprilus alepidotus), but can be distinguished by its much lower dorsal and tail fin.

It travels in small bands or loosely organized schools, preferring sandy-bottomed areas to muddy ones, and often coming close to shore.

The American butterfish spawns in the Gulf of Maine during the summer months, peaking in July.

Fry are 2 mm (0.079 in) long at hatching, and by autumn, have grown to a length of 3–4 in (7.6–10.2 cm).