Check what the local agency documents.
Official fish and fishing resources for the western states. Species presence, stocking and rules depend on the specific water and reach.
Photo credit
Rainbow trout from the Big Hole River near Twin Bridges, Montana. Photo: Mike Cline, public domain, cropped, via Wikimedia Commons
10 official state resources
MontanaMontana fish species & regulationsOfficial state fish and wildlife resource · verify species and reach on sourceCaliforniaCalifornia freshwater fishingOfficial state fish and wildlife resource · verify species and reach on sourceColoradoColorado fish species and fishingOfficial state fish and wildlife resource · verify species and reach on sourceIdahoIdaho fish and fisheriesOfficial state fish and wildlife resource · verify species and reach on sourceNevadaNevada fish and fishing watersOfficial state fish and wildlife resource · verify species and reach on sourceNew MexicoNew Mexico game fishOfficial state fish and wildlife resource · verify species and reach on sourceOregonOregon fish speciesOfficial state fish and wildlife resource · verify species and reach on sourceUtahUtah fish and water informationOfficial state fish and wildlife resource · verify species and reach on sourceWashingtonWashington fish and fishingOfficial state fish and wildlife resource · verify species and reach on sourceWyomingWyoming fish and fishing regulationsOfficial state fish and wildlife resource · verify species and reach on source