Dwarf hygrophila

Quick facts

Max height

50 cm

Growth rate

fast

Difficulty

beginner

Placement

background

Propagation

stem cuttings

Water parameters

Temperature

18–28°C

pH

6.0 to 8.0

Hardness

2 to 25 dGH

Cold water

tolerated (unheated setups)

Light and nutrients

Lighting

low

CO2

not required, but boosts growth and color

Substrate

inert ok

Feeding

feeds from both water column and roots (liquid ferts plus root tabs)

Substrate

What this plant roots into (or attaches to). The substrate affects both plant nutrition and water chemistry; see each linked page for full effects.

This plant feeds primarily from the water column, so substrate choice matters more for its fish-tank compatibility than for plant nutrition.

With fish

Plant-eating fish

safe with plant-eating fish (tough leaves or unpalatable)

Diggers (corydoras, loaches)

fine - root system or attachment style handles it

Root-disturbing fish

tolerates fish that disturb roots

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

This species transitions to outdoor ponds well, not just indoor aquariums.

Outdoor pond zones (USDA)

8 to 13 (winter low around -12°C or warmer)

Below the minimum zone, the plant won't overwinter outdoors but can still be grown seasonally and overwintered indoors. Several pond-friendly species (water hyacinth, water lettuce, parrot's feather) are regulated as noxious in some jurisdictions; check the legality data on the profile before releasing anything to an outdoor body of water.

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.

Further reading

• How to cycle a fish tank
• Water chemistry for fishkeepers: pH, GH, KH, and what they mean