[5] Minimally the subspecies may have evolved postglacially from populations that survived glaciation in Southern Alberta or Montana in the upper Missouri drainage basin, and be younger than 9500 BP.

[5] Maximally it may have survived the Wisconsin glaciation in a local or larger eastern slope Alberta refugium and be much older.

[3][7] This fish's range was limited to an outlet marsh that the Cave and Basin Hotsprings drain into, and that lead into the Bow River.

[5] This study posits that based on these results most of the Banff longnose dace were either extirpated or hybridized between the years of 1925-1971.

[5] A collection survey conducted, on behest of Don E. McAllister, in a marsh below the hotsprings on June 1, 1968 did not report any Banff longnose dace.

[10] Don E. McAllister suggests in a 1970 publication that the Banff longnose dace may be extinct, and posits the cause as the introduction of tropical fish.

[7] The development of a popular thermal swimming pool at the Cave and Basin National Historic Site eventually led to chlorine leakage into the dace's habitat.

[13] Human waste from heavy usage of the springs, coupled with a lack of adequate treatment facilities, may have had a negative impact on the dace's habitat.

[5] Deliberate introduction of western mosquitofish for mosquito control in 1924[10][14] was followed by the release of various tropical fish including the sailfin molly, green swordtail, angelfish, guppies, zebra cichlid, Siamese fighting fish, blue gourami, and African jewelfish[15][5] (and aquarium plants).

[5] Results and enquiries made during a collection survey done on June 1, 1968 suggested that the introduction of tropical species, other than the mosquitofish, may have occurred from 1958-1967.

[10] The introduced exotic fish competed with the dace for food, nesting sites, and preyed on unhatched eggs.