Curly waterweed (Lagarosiphon major) care guide

Group
Plants
Other names
Curly waterweed, African elodea, Oxygen weed, South African oxygen weed, Elodea crispa
Family
Hydrocharitaceae (frogbit family)
Origin
Southern Africa (Zimbabwe, Botswana, Lesotho, South Africa)
Water
freshwater
Temperature
10–24°C
pH
7–8.5
Hardness
8–20 dGH
Care level
beginner
Lighting
Medium to high light; CO2 not needed

Care

Legal note: this plant may not be sold on Aquatic-Auctions to buyers in Great Britain. It is on the GB list of invasive species (check GOV.UK for the current rules). Curly waterweed is a fully submerged oxygenating plant from southern Africa, long sold for ponds and coldwater tanks under the name Elodea crispa. It has been widely spread through the aquarium and pond trade and is now a serious invasive weed in several countries. It is on the EU list of invasive alien species of Union concern, a pest plant in New Zealand and a noxious weed in the USA, and it is recorded wild in Ireland. In tanks it forms dense stands of stiff stems with curled-back leaves, used in the background or left floating. It prefers cool, hard, alkaline water and good light, and suits unheated tanks and ponds better than warm tropical aquariums. Water figures are our estimate, not from the sources. Never release it or put trimmings in drains or waterways; dispose of unwanted material by drying or composting away from water. Sources: Wikipedia (en.wikipedia.org/wiki/Lagarosiphonmajor); Wikipedia (en.wikipedia.org/wiki/Lagarosiphon); Wikipedia, List of freshwater aquarium plant species. Checked October 2026.

Breeding

Spreads very easily from stem fragments, which is how it invades new waters. In cultivation simply plant cuttings. Plants are male or female; outside its native range spread is almost entirely by fragments.

Compatibility and tank mates

Best in unheated or coldwater tanks and ponds with temperate fish such as minnows, sticklebacks or small goldfish; large goldfish and koi may eat or uproot it. It suits tropical tanks poorly over the long term.

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

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