The Dollar Sunfish is a pint-sized species of sunfish found in the south. It grows to only 4 or 5 inches in length, maximum. 

The Dollar Sunfish looks very similar to a Longear Sunfish. In fact, the two species have their own taxonomic subgenus to themselves, called Icthelis.  To tell them apart, count the rays on the pectoral fin - Longears have 14-15 pectoral fin rays while the Dollar Sunfish will have only 12. Dollars also have 3-4 rows of scales on their cheek versus 5-6 in the Longear. Dollar sunfish also sport a number of wavy blue lines or specks on the opercular flap, while longear sunfish will have a purely black operculum.