This long- and narrow-leaved plant resembles Vallisneria nana but belongs to the “chain swords” of the genus Helanthium. It entered the aquarium hobby in Europe in the 1960s under the name Echinodorus angustifolius. Nowadays it is rather rarely available. It is an amphibious plant that’s said to originate in the Brazilian state of Mato Grosso. When it falls dry, it develops its emersed stage with much shorter, lanceolate aerial leaves and inflorescences with white flowers. The light to medium green, strap-shaped underwater leaves get more than 50 cm long and about 3-4 mm wide. This rosette plant sprouts long runners with a chain of many young plants above the bottom. It is the wild type of the cultivar ‘Vesuvius’ that was selected in the nursery Oriental in Singapore.

The Narrow-leaf swordplant is a quite easy, fast growing aquarium plant. Medium lighting is sufficient, the favourable temperatures lie between 20 and 28 °C and the carbonate hardness may reach about 12 °KH. As well as other plants of the Alismataceae family, it benefits much from a nutrient-rich bottom. An adequate iron supply is important to prevent chlorosis (pale green new leaves). Favourable conditions lead to rampant growth of runners that can be cut off before they get out of hand.

Helanthium bolivianum ‘Angustifolius’ looks decorative as a grass-like, freshly green stand in the background of an aquarium. The long leaves look especially well in tall tanks (more than 60 cm high). In lower aquariums they form long floating swathes beneath the surface. This classic aquarium plant is occasionally used for aquascapes in the Japanese nature aquarium style.