Banded pygmy sunfish
(Elassoma zonatum)

The banded pygmy sunfish, Elassoma zonatum, is a species of pygmy sunfish endemic to the United States, where it is found from Indiana and Illinois to Texas to the Atlantic coast. It prefers densely vegetated bodies of slow-moving water. This species can reach 4.7 cm (1.9 in) in total length, though most do not exceed 3.5 cm (1.4 in).

The banded pygmy sunfish are capable of retaining their juvenile characteristics while they are sexually mature; that is to say that they are neotenous.

It was originally thought that the banded pygmy sunfish belonged to the cichlid family. However, researchers Hay, Jordan, and Gilbert thought that the banded pygmy sunfish was actually an intermediate species of fish between the pirate perch and the centrarchid family of fishes. Therefore, the banded pygmy sunfish was placed into its own family, Elassomatidae. In the 5th edition of Fishes of the World, though, this is treated as a subfamily of the sunfish family Centrarchidae.

Distribution
The banded pygmy sunfish is a small fish that can live in rivers, streams, lakes, ponds, and even swamps. This species is historically found only in the continental United States, with relatively little change in distribution. One exception to this is minor decreases in species distribution due to habitat loss. They have historically been residents of the Mississippi River drainage system and Gulf coastal plain region.

Currently, they are found from the lower Roanoke River drainage in North Carolina to the southern to middle parts of the St. Johns River in Florida. Also, they are found west to the Brazos River drainage in Texas and north to lower Wabash River drainage in Indiana and Illinois.

Being a member of Elassomatidae, this species of pygmy sunfish is similar in habitat preferences. It prefers to live in slower to still water conditions with higher sedimentation content, hence the swamps and ponds. However, the human development of wetland habitat over the ages has caused a decrease in banded pygmy sunfish and other pygmy sunfish habitat. Though the banded pygmy sunfish can retreat to lakes, streams, and rivers when wetlands are being drained, they need the wetlands for breeding. Thus, the true reason for the disappearance of the banded pygmy sunfish from certain areas is not just a loss of any habitat, but the loss of its breeding habitat. When this happens, the population eventually dies off, leaving an area that can no longer support the species.