Stratiotes aloides, or water soldier, is an aquatic freshwater perennial plant in the family Hydrocharitaceae that forms dense floating mats during summer. It is an invasive non-native species in Canada. This article documents the case of an artificial pond in the Eastern Townships region of southern Québec that rapidly became densely colonized by this species. By examining photographs, it was possible to confirm the presence of one specimen in 2013 and to document its spread until 2019, when the pond was entirely covered. These observations add a new mention of the presence of water soldier in Québec and suggest that this plant can spread quickly. They also show the need to prevent introductions, to monitor the progress of already established populations, and to possibly implement methods to reduce or eradicate the species.