It is generally found in lakes and streams in northeastern part of the United States and along the Mississippi River systems.

[2] The pectoral fins in this darter species may function in vertical movement, as well as in low-speed maneuvering, as these fish lack swim bladders.

[4] The fish species, Etheostoma microperca, is distributed across the northeastern part of the United States, particularly in the midwest.

[5] Adults of E. microperca are usually found in streams near vegetation, such as along overhanging grassy banks and among filamentous algae.

[6] They mainly reside in natural lakes and permanent wetlands that contain large amounts of aquatic vegetation and clear waters.

The preferred prey are Batidae nymphs, Tanytarsini (e.g. Tantarsus) and Orthocladiinae (e.g. Corynoneura, Cricotopus).

They also develop lateral flaps of skin on their pelvic fins as early as late January, and by mid-March their breeding colors are evident.

They are vulnerable to pollution, pesticides, agricultural and urban runoff, eutrophication, and loss of habitat elements, such as low-velocity waters and aquatic vegetation.

Water systems with large populations of least darters should be protected from human disturbances and development.

Prior to 1990, the least darter was known from 31 sites in 10 streams and 9 lakes scattered across the southern three-fourths of the state.

Additionally, the identification of specific environmental stressors is needed to further understand how to aid the fish populations.