Dwarf hairgrass

Quick facts

Max height

10 cm

Growth rate

moderate

Difficulty

intermediate

Placement

foreground

Propagation

runners

Water parameters

Temperature

18–28°C

pH

6.0 to 7.5

Hardness

2 to 15 dGH

Light and nutrients

Lighting

high

CO2

not required, but boosts growth and color

Substrate

nutrient rich

Feeding

feeds from both water column and roots (liquid ferts plus root tabs)

Substrate

What this plant roots into (or attaches to). The substrate affects both plant nutrition and water chemistry; see each linked page for full effects.

This plant feeds primarily from the water column, so substrate choice matters more for its fish-tank compatibility than for plant nutrition.

With fish

Plant-eating fish

safe with plant-eating fish (tough leaves or unpalatable)

Diggers (corydoras, loaches)

may get uprooted by active diggers

Root-disturbing fish

sensitive to root disturbance, plant where roots stay undisturbed

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.

Further reading

• CO2 injection for planted tanks: what it costs, what it does, and when to skip it