Potamogeton gayi is a narrow-leaved pondweed from southern South America. Although long known as reliable, undemanding aquarium plant, it is rather rarely available in recent times. The plant forms a dense stand in short time and propagates by underground runners. The grass-like narrow leaves are green to brown-red.

Gay's pondweed has only little demands and grows also in hard water. CO₂ supply is not necessary but promotes the growth. Potamogeton gayi comes from subtropical areas with quite cool winters, so it can be used in unheated tanks. It is especially recommended for the midground and background of natural layouts as well as for breeding tanks. As it spreads by runners, it should be placed with a sufficient distance from slow-growing, low and ground-covering plants