The blacktail shiner (Cyprinella venusta) is a small freshwater fish in the family Cyprinidae native to the United States.

Aquatic insects and algae were the most common food items of blacktail shiners in the Blanco River, Texas; sediment and detritus were found in 21% of the 36 guts examined.

Blacktail shiners may serve as major food resource for piscivorous spotted bass (Micropterus punctulatus) during the summer in Village Creek (Neches River), Texas.

[8] The blacktail shiner is most common in pools and runs of clear, sandy-bottomed, small to medium rivers, typically in areas with sparse vegetation and strong current, but upland populations occur in creeks over substrates with more gravel and rubble.

Blacktail shiner mesohabitat is ubiquitously distributed among pools, runs, and riffles with silt, gravel, and bedrock substrates.

In the Blanco River, Texas, blacktail shiners were most abundant in swift runs in the spring and summer.

[7] The species occurred throughout the year in riffle and sandbank habitats in Village Creek (Neches River), Texas.

[12][13] In Village Creek, Texas, blacktail shiners revealed size distribution patterns consistent with a protracted spawning season.

[14] In the Blanco River, Texas, blacktail shiners were observed depositing eggs underneath small boulders and large cobble in a bedrock riffle in the swiftest current velocities available.

[15][16] Activities such as construction and operation of hydroelectric facilities, flood control, additional irrigation diversions, bank stabilization, oil and gas drilling, mining, grazing, stocking or introduction of nonnative fishes may jeopardize the continued existence of the blacktail shiner.