Dwarf hygrophila
Hygrophila polysperma
Also known asIndian swampweed · Hygro · Miramar weed (US invasive name)
Water parameters
Light and nutrients
Substrate type: inert ok. Propagation: stem cuttings.
Substrate compatibility
| Substrate | pH effect | Nutrient load |
|---|---|---|
| Inert sand (Pool filter sand) | neutral / inert | none |
| Inert gravel (Aquarium gravel) | neutral / inert | none |
| Aquasoil (ADA Amazonia) | lowers pH | very high |
| Mineralized clay substrate (Seachem Fluorite) | neutral / inert | moderate |
| Dirted tank (mineralized topsoil) (DIY soil substrate) | slightly acidic | very high |
With fish
Origin and habitat
Native to the Indian subcontinent, found in marshes, ditches, rice paddies, and slow-moving waterways across India and Southeast Asia. The species (Hygrophila polysperma) is a small-leaved stem plant with opposite pairs of oval to lanceolate leaves (2–4 cm long) along a thin, upright stem. Submerged leaves are light green; under strong light, the leaf tips and upper portions develop pink to reddish tones, especially in the 'Rosanervig' (pink-veined) cultivar. Hygrophila polysperma is one of the fastest-growing aquarium plants available, which contributes to its reputation as both a great beginner plant and an invasive weed. The species is listed as a federal noxious weed in the United States, making it illegal to sell or transport across state lines. Despite this designation, it remains widely available from hobbyist trades and some retailers.
Outdoor pond use
- USDA zones
- 8–13 (winter low around -12°C or warmer)
Care notes
Extremely easy. Grows under any conditions: low to high light, no CO2, any water chemistry (pH 5.5-8.5, soft to very hard), temperature 18–30°C. Growth is fast to explosive under moderate light with nutrients, often requiring trimming 2-3 times per week in high-tech setups. The speed of growth makes it one of the most effective nutrient-export plants available, rapidly pulling nitrate and phosphate from the water column. Plant stems in groups, pushed into substrate. Trim tops and replant cuttings to propagate. The cut lower stems produce multiple side shoots, creating increasingly bushy growth with each trim cycle. The 'Rosanervig' cultivar develops attractive pink veining under high light, making it one of the more interesting-looking Hygrophila forms. The federal noxious weed designation in the US creates a legal gray area: the plant is widely grown in home aquariums but technically illegal to transport. Enforcement is rare, and many hobbyists are unaware of the restriction. Outside the US, it's legal and widely available. If you can grow it legally, H. polysperma is one of the most useful plants for establishing a new tank, competing with algae, and exporting nutrients.