Dwarf hairgrass
Eleocharis parvula
Also known asEleocharis acicularis
Water parameters
Light and nutrients
Substrate type: nutrient rich. Propagation: runners.
Substrate compatibility
| Substrate | pH effect | Nutrient load |
|---|---|---|
| Aquasoil (ADA Amazonia) | lowers pH | very high |
| Mineralized clay substrate (Seachem Fluorite) | neutral / inert | moderate |
| Inert sand (Pool filter sand) | neutral / inert | none |
With fish
Origin and habitat
Distributed across temperate and subtropical regions worldwide. The genus Eleocharis includes many species; the ones sold as 'dwarf hairgrass' are typically E. acicularis (which also has its own separate listing as a taller form) or E. parvula/E. pusilla (true dwarf forms that stay shorter). The plant grows as thin, grass-like blades (1–10 cm tall depending on species and light) from a network of spreading runners that form a dense mat. In the wild, Eleocharis species grow in wet meadows, pond margins, and shallow water. In the aquarium hobby, dwarf hairgrass is one of the most popular carpeting plants, creating a lawn-like effect across the foreground. The distinction between dwarf Eleocharis species is often unclear in the trade; many shops sell E. acicularis (the taller form) labeled as 'dwarf hairgrass.' True dwarf forms (E. parvula, E. pusilla) stay under 5 cm, while E. acicularis reaches 15 cm. Tissue culture cups are the most reliable way to get a specific species.
Care notes
A demanding carpeting plant that performs best with CO2 injection and high light. Without CO2, dwarf hairgrass grows very slowly and often fails to carpet, instead forming sparse tufts that never connect. With CO2 at 20-30 ppm and high light (70+ PAR at substrate level), the plant sends out runners rapidly and forms a dense, lawn-like carpet within 6-10 weeks. Plant small plugs (split tissue culture cups into 8-12 portions) 2–3 cm apart across the foreground. Rich substrate is important because the plant is a root feeder; aquasoil or a capped nutrient layer produces the best results. Root tabs supplement nutrition in inert substrates but aren't as effective as a nutrient-rich base layer. Trim the carpet with scissors when it grows too tall (above 4–5 cm); trimming promotes horizontal runner growth and denser coverage. The trimmings can be replanted but are fragile. Old, thick carpets can develop dead zones underneath where light doesn't penetrate; thin them occasionally. Temperature: 18–28°C. Prefers soft to moderately hard water. In low-tech tanks without CO2, consider Monte Carlo or dwarf sagittaria as easier carpet alternatives.