Eightstem Pondweed

Eightstem pondweed is one of the true pondweeds of the genus Potamogeton, a group most aquarists meet as backyard-pond plants rather than aquarium subjects. The name octandrus points to the flower rather than the foliage: the suffix -andrus marks the stamens, which the original description counted as eight. The narrow, grass-like leaves grow alternately along the stem, and the plant builds into a soft green thicket that reads more like a wild plant than a designed aquarium one.

It is very widely distributed across the Old World, from Africa through Asia to Australia, growing in still and slow-moving freshwater. It spreads by runners along the substrate and by stem cuttings. It tolerates a broad temperature range of about 10 to 26 °C and neutral to slightly alkaline water, making it a candidate for cool, unheated tanks.

There is little published cultivation detail for this species, and the standard plant database flags it as restricted for aquarium use, so the care figures here are estimates. In a cool, low-light tank it grows steadily without CO₂ and asks for little, but it lacks the tidy habit of most stem plants sold for the background.