Marsh dewflower, Marsh dayflower, Asian spiderwort, Aneilema keisak
Family
Commelinaceae (spiderwort family)
Origin
East Asia: China, Japan, Korea and Tibet
Water
freshwater
Maximum size
20 cm
Temperature
15–28°C
pH
6–7.5
Hardness
2–15 dGH
Care level
beginner
Lighting
Medium light; CO2 and strong light give red tips
Care
Marsh dewflower is an annual of freshwater marshes and pond and stream edges in East Asia, often found in rice fields. It has fleshy, sprawling stems that root at the lower nodes and small white, pink or blue-purple three-petalled flowers. Tropica stresses that it is a stem plant, not a grass, despite its grass-like look. Tropica rates it easy, reaching 5–20 cm in two months. It has light green leaves about 1 cm wide and 3–5 cm long and grows upright, branching when cut back. Shoot tips turn reddish with CO2 and strong light. It grows fast and needs regular trimming. Water figures are our estimate, not from the sources. It is invasive in the USA, where it forms dense mats from New Jersey to Florida and along the Columbia River. Never release this plant or dispose of it in drains or waterways; it is invasive in some countries. Sources: Tropica (tropica.com/en/plants); Wikipedia (en.wikipedia.org/wiki/Murdanniakeisak); Wikipedia, List of freshwater aquarium plant species. Checked October 2026.
Breeding
Cut back and replant the tops; it also spreads by rooting stems and by seed.
Compatibility and tank mates
Goldfish, large cichlids, silver dollars and other plant-eating fish will graze soft stems, and diggers can uproot new cuttings. Most small community fish, shrimp and snails leave it alone, and shrimp and fry use the foliage for cover.
Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.
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