Longnose dace eat algae and aquatic insects and are important forage minnows for larger predatory fish.

However, longnose dace (like all members of the family Cyprinidae) lack small fleshy projections, called papillae, on their mouths.

Juveniles have a black lateral line that extends from the beginning of the eye to the caudal fin that fades as the fish matures.

Both adult males and females may have bright orange-reddish colouration at the base of pectoral, pelvic, and anal fins and on the upper lip.

Longnose dace prefer shallow, fast-moving riffles in streams and rivers and the turbulent, near-shore region of lakes.

In the Oldman River, some longnose dace populations are characterized by elevated vitellogenin expression, female biased sex ratios and intersex gonads.

[16][17] Feminization is likely caused by estrogen-like compounds present in municipal wastewater effluent, agriculture, and cattle operations near the Oldman River, however this mechanism is not well understood.

It is not known if increased vitellogenin expression and intersex gonads significantly decrease reproductive success and will impact the long term viability of longnose dace in these systems.