Aquatic PlantsIntermediate🌤️ Bright indirect
Dwarf hairgrass
Eleocharis parvula · also called Dwarf spikerush, Hairgrass, Eleocharis pusilla
Generally non-toxic to cats and dogs.
A fine grass-like carpeting sedge that spreads by runners to form a lush, lawn-like foreground. With strong light and CO2 it carpets densely and stays short; under lower light it grows taller and thinner. Note that E. parvula is a distinct, shorter species from the taller, needle-like E. acicularis, though both are sold as 'dwarf hairgrass'.
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Quick facts
| Category | Aquatic Plants |
| Family | Cyperaceae |
| Native origin | Cosmopolitan; native across North, Central and South America, Europe, North Africa and Asia, typically in salt marshes, mudflats and brackish-tolerant shallows |
| Care difficulty | Intermediate |
| Light | Bright indirect |
| Pet toxicity | Pet-safe |
Light
Medium-to-high light (roughly 40-80+ PAR at substrate). Under high light it stays short and creeps horizontally to form a tight carpet; under low light it etiolates, growing long and sparse. In a fixed light scale this maps to the brightest/high-light tier for a true dense lawn (the 'bright_indirect' value here is used as the closest high-light option).
Water
Temperature 10-26 C (ideal 20-24 C), pH 6.5-8.0, soft to moderately hard water (roughly 2-15 dGH). As a salt-marsh species it is very adaptable and tolerates slightly brackish conditions, though it is grown freshwater in aquaria. Benefits from a comprehensive water-column fertiliser (especially iron and potassium) once carpeting.
Soil & potting
Plant individual culms/runners into a nutrient-rich substrate; fine-grained aquasoil, or sand capped over nutrient soil, is ideal. Root tabs help in inert gravel or sand. Roots are shallow but spread aggressively via runners (stolons) just under the surface. Divide tissue-culture mats into small clumps and dot them 2-3 cm apart for faster coverage. This is a substrate-rooted plant, not an epiphyte, so the runners and roots are planted into the substrate.
Environment — humidity, temperature, placement
CO2 is not strictly required but is strongly recommended for a fast, dense, short carpet; without CO2 expect slower, taller growth and a looser carpet. Gentle-to-moderate flow keeps detritus off the blades. Foreground-to-midground placement. Grows readily emersed (often sold emersed) and transitions to submersed.
Propagation
Spreads by horizontal runners (stolons) that send up new vertical shoots, knitting into a carpet. Propagate by lifting and dividing the mat into smaller plugs and replanting. Trimming the tops with scissors encourages denser, lower growth.
Toxicity detail
Non-toxic to fish, shrimp and pets; shrimp graze biofilm on the blades. Not listed as a regulated/invasive species in the mainstream aquarium trade, but as a vigorous, runner-spreading wetland sedge with a near-global distribution it should never be released into the wild. Dispose of trimmings in the trash, not in waterways.
Growth stages
How this plant changes through its life — each stage often has its own care, diet and space needs.
Sources
- Tropica - Eleocharis acicularis / parvula plant database (care guide)
- Wikipedia - Eleocharis parvula (encyclopedia)