American pillwort (Pilularia americana) care guide

Group
Plants
Other names
American pillwort
Family
Marsileaceae (water-clover family; a fern)
Origin
California and south-central Oregon, with scattered records in eastern North America; possibly Central and South America
Water
freshwater
Maximum size
8 cm
Temperature
10–26°C
pH
6–7.5
Care level
intermediate
Lighting
Medium to high light; CO2 helpful

Care

American pillwort is a tiny aquatic fern related to Marsilea. It looks like grass: its fronds are only thin stalks with no leaf blade, unrolling from a coil like other ferns. It grows rooted in shallow water or wet mud, above or below the water, and may die back in dry or cold seasons. Recent work suggests the plants called by this name may be more than one species. The sources do not describe aquarium use, but it can be used like other small grass-like plants as a low foreground carpet, or emersed in paludariums. Plant small clumps in a fine substrate and give good light. The maximum size given is an estimate of frond height. Water figures are our estimate, not from the sources. Sources: Wikipedia (en.wikipedia.org/wiki/Pilulariaamericana); Wikipedia, List of freshwater aquarium plant species. Checked October 2026.

Breeding

Spreads by a creeping rhizome, which can be divided. It also forms hard, pea-like spore cases (sporocarps) that survive drying and sprout the following season.

Compatibility and tank mates

Small and delicate, so digging fish will uproot it. Suits shrimp tanks and small fish. Tolerates cooler water as well as tropical temperatures.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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