Elodea (Elodea densa) care guide

Group
Plants
Other names
Egeria densa, Brazilian waterweed, Large-flowered waterweed, Pondweed, Anacharis densa
Family
Hydrocharitaceae (frogbit family)
Origin
Warm temperate South America: south-eastern Brazil, Argentina, Chile and Uruguay
Water
freshwater
Maximum size
100 cm
Temperature
16–28°C
pH
6.5–8
Hardness
5–20 dGH
Care level
beginner
Lighting
Low to high light; CO2 not needed

Care

A submerged waterweed from warm temperate South America (south-eastern Brazil, Argentina, Chile and Uruguay). The name is used both ways: Tropica sells it as Egeria densa, the name the list notes as now usual, while Wikipedia currently files it under Elodea densa with Egeria densa as a synonym. The page key keeps the listed name. It forms long, brittle stems with whorls of four to eight bright green leaves. In the wild stems can exceed 2 m; Tropica gives 40–100 cm in an aquarium. Use it in bunches at the back of the tank or let some stems float. Tropica rates it as easy and good for beginners. It needs only low light and no added CO2, grows fast and takes up a lot of nutrients, which helps hold back algae in new tanks. In poor light or with too few nutrients it keeps growing but goes pale and spindly. It grows best at about 16–28 °C and slows above 32 °C, so it suits both coldwater and tropical tanks. The pH and hardness figures are our estimate, not from the sources. Never release this plant or dispose of it in drains or waterways; it is invasive in some countries. It forms dense mats in lakes and rivers in many warm countries and regrows from small fragments. Sources: Tropica (tropica.com/en/plants); Wikipedia (en.wikipedia.org/wiki/Elodeadensa); Wikipedia, List of freshwater aquarium plant species. Checked October 2026.

Breeding

Cultivated plants are all male clones, so it is spread only by cuttings. Separate bundled stems, strip the leaves from the lowest 5 cm and plant each stem a little apart; roots soon form. Pieces left floating also root and grow.

Compatibility and tank mates

Goldfish, koi, large cichlids, silver dollars and plant-eating snails will eat it, but it often grows fast enough to keep up and is cheap food for goldfish. Suits coldwater and tropical tanks and ponds where it is legal; livebearer fry and shrimp shelter in its stems.

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

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