The Santa Ana speckled dace historically occurred in the basin, foothill, and higher elevation portions of the Los Angeles, Santa Ana and San Gabriel River systems, but currently only occurs in the headwaters of the Santa Ana and San Gabriel Rivers. It occurs in Lytle, Cajon, City and Plunge Creeks. This species is rare due to habitat loss and degradation.

Santa Ana speckled dace is a fish species that is found primarily in small perennial streams. They thrive in shallow creeks with runs of gravel and cobble substrates where they eat invertebrates, such as insect larvae or nymphs, and algae. They can be active year-round, as long as water temperatures are above 39° F, and spawn throughout the summer, with peaks in June and July

The primary threats the Santa Ana speckled dace include water diversion, urbanization and introduction of nonnative species. Management includes protecting creeks, streams and rivers, habitat restoration, removal of nonnative species and captive headstarting.