This fish can reach about 30 cm in length, but it is usually smaller, often around 7 cm. It is mature at 2 to 4 years of age, and its maximum lifespan is around 7 years. It is brown, gray, or olive green on its upper parts and white or yellowish ventrally. There are dark spots or bars on the back and dark bars on most of the fins. The body of the fish is prickly; inland-dwelling fish tend to be more prickly than those at the coast.
Fun Fact The inland form is generally more densely prickled over a larger portion of the body while the coastal form shows a reduced number of prickles.