The longfin dace (Agosia chrysogaster) is a species of leuciscid fish found in southwestern North America.

[4] Age estimation with scales and length-based grouping suggested that most longfin dace live less than two years.

[6] The longfin dace is tolerant to a wide range of water temperature, and is found in low elevation desert streams to mountain brooks.

[4] They prefer streams that have sandy or gravel bottoms, typically with overhanging banks or cover to use as protection.

In the United States, longfin dace are considered secure but have been reduced in abundance due to habitat change and introduced fishes.