 The original distribution downstream is unknown with no records of the species in areas that have been colonised by introduced trout, including adjacent catchments within the overall Thomson River system.Within its range, "G.lanceolatus" is the only member of the mountain galaxias species complex; the Shaw galaxias ("G.gunaikurnai") occurs in a geographically isolated headwater tributary of the Macalister River some east of Stoney Creek but still within the Thomson River basin.Other native species found in the same catchment include climbing galaxias ("G.brevipinnis"), short-finned eel ("Anguilla australis"), central highlands spiny crayfish ("Euastacus woiwuru"), Gippsland spiny crayfish ("Euastacus kershawi") and common freshwater shrimp ("Paratya australiensis").