Pearlweed (Hemianthus micranthemoides) care guide

Group
Plants
Other names
Micranthemum glomeratum (the plant sold as pearlweed), Micranthemum micranthemoides, Nuttall's mudflower, Pearl grass, Baby tears
Family
Linderniaceae (false-pimpernel family)
Origin
The aquarium plant (Micranthemum glomeratum) is from Florida; the true H. micranthemoides was from the mid-Atlantic USA
Water
freshwater
Maximum size
20 cm
Temperature
20–28°C
pH
6–7.5
Hardness
2–12 dGH
Care level
intermediate
Lighting
Medium to high light; moderate CO2 (about 6–14 mg/L) recommended

Care

Name note: the plant sold as pearlweed under this name is not Hemianthus micranthemoides. Wikipedia explains that aquarium "pearlweed" was identified as Micranthemum glomeratum, a plant native to Florida, while the true H. micranthemoides (now Micranthemum micranthemoides, Nuttall's mudflower) was a small annual of tidal mudflats from Virginia to New York that has not been seen since 1941 and is considered extinct. The page key keeps the listed name; Tropica sells the plant as Micranthemum glomeratum and notes its old name. Pearlweed has small, light green, slightly arched leaves on fine stems 10–20 cm tall and 2–3 cm wide, a little like a miniature Egeria. It makes soft, bushy groups in the midground. In strong light it creeps, so it can also be trained as a foreground cover, and in a terrarium it forms a compact cushion. Tropica rates it as advanced, with a medium growth rate and medium light and CO2 needs; it does best with good light and regular trimming to stay dense. Water figures are our estimate, not from the sources. Sources: Tropica (tropica.com/en/plants); Wikipedia (en.wikipedia.org/wiki/Hemianthusmicranthemoides); Wikipedia, List of freshwater aquarium plant species. Checked October 2026.

Breeding

Propagated from cuttings: trim shoot tips and replant them in small bunches. Regular trimming also makes the clump bushier.

Compatibility and tank mates

Delicate; goldfish and large plant-eaters will eat it, but community fish, shrimp and small snails leave it alone. Popular in shrimp tanks.

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

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