The Bayou darter (Etheostoma rubrum) is a rare species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches.

It is endemic to western Mississippi in the United States, where it is found only in Bayou Pierre and its tributaries.

The population of this fish is declining due to loss of suitable habitat.

[3] Associated fish species include brighteye darter (Etheostoma lynceum), least madtom (Noturus hildebrandi), bluntface shiner (Cyprinella camura), and redspot darter (Etheostoma artesiae).

[6] The Bayou darter eats insects and their larvae, including caddisflies, blackflies, midges, and mayflies.

Agriculture, especially silviculture affect the area by destroying riparian habitat, causing erosion and increasing sedimentation.