I recently learned of a now extinct longnose dace subspecies that has me puzzled. It was found in a marsh in Banff National Park in Alberta Canada before a combination of introduced tropicals, a chlorine spill from a pool, and a beaver dam blocking fish movements killed it off.

But what puzzles me is the habitat. From what I read the marsh was warm (the water in it came from hot springs), had a mud bottom, and had very weak current. Three things longnose dace do not like. Longnose dace like current, the faster the better. When in lakes they are found in either wave beaten shores or where islands concentrate current. They love rocky areas for cover and need rocks to spawn, this marsh was mud bottomed and heavilly vegetated. They tend to like cool water conditions and this was hot spring run off.

So I am confused. This now dead subspecies was found in the complete opposite of the species normal habitat. Why?