valisneria

Valisneria is a genus of aquatic plants in the family Hydrocharitaceae, commonly known as valisneria or eelgrass. Native to tropical and temperate freshwater habitats across several continents, the genus is widely used in home aquariums for its hardiness, rapid growth, and natural background effect.

Description and biology: Valisneria species are perennial submerged plants that spread via creeping runners. They produce long, ribbon-like leaves that can extend from base rosettes and reach substantial lengths in nature. The genus is dioecious, with separate male and female plants. Reproduction typically involves a stalk from a male flower rising to the water surface and releasing pollen to floating female flowers on stalks; fertilized fruits develop and seeds sink or drift away.

Habitat and ecology: In the wild, Valisneria favors slow-moving or still waters, often in sandy or muddy substrates with adequate light. In established communities, dense stands provide shelter for small aquatic life and contribute to oxygenation. They are generally tolerant of a range of water conditions but prefer bright light and stable substrates.

Cultivation and care: In aquariums, Valisneria is valued for rapid, undemanding growth and easy propagation by runners. Provide bright to moderate lighting and a nutrient-rich substrate; carbon dioxide supplementation is beneficial but not essential. Regular trimming helps prevent overshadowing of other plants and keeps the stand tidy. They tolerate a wide temperature range (roughly 20–28°C) and a broad pH span.

Species and varieties: The genus includes Valisneria spiralis, Valisneria americana, Valisneria gigantea, and Valisneria nana, among others. In cultivation, many cultivars derive from V. americana selections.