Bacopa monnieri

Quick facts

Max height

25 cm

Growth rate

moderate

Difficulty

beginner

Placement

midground

Propagation

stem cuttings

Water parameters

Temperature

18–28°C

pH

6.0 to 8.0

Hardness

3 to 20 dGH

Brackish

tolerated

Cold water

tolerated (unheated setups)

Light and nutrients

Lighting

medium

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 wetlands across tropical and subtropical regions worldwide, from India and Southeast Asia through Africa to the Americas. Found in shallow water, marshes, and wet soil from sea level to moderate elevations. The species (Bacopa monnieri) is famous outside the aquarium hobby as the Ayurvedic herb Brahmi, used in traditional Indian medicine for cognitive enhancement. The plant has small (0.5–1 cm), rounded, succulent leaves arranged in opposite pairs on creeping stems. It's smaller and more delicate in appearance than the related Bacopa caroliniana. Submerged growth produces lighter green, slightly elongated leaves. The plant flowers above water with small white to pale blue blooms.

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

Very easy stem plant that grows in virtually any conditions. Low to high light, soft to hard water, with or without CO2. Growth under low light is slow but the plant survives and maintains itself. Under moderate light with some liquid fertilizer, it grows at a steady pace. Under high light with CO2, growth is fast and the plant becomes bushier with tighter leaf spacing. The stems are thinner than Bacopa caroliniana, giving the plant a more delicate appearance. Plant in groups of 5-10 stems. Trim tops and replant cuttings to propagate. The creeping growth habit means stems may grow horizontally before turning upward, creating a cascading effect along the substrate. This is natural and can be aesthetically useful in aquascaping. Not demanding about nutrients; moderate liquid fertilizer and occasional root tabs are sufficient. The dual-use aspect (aquarium plant and medicinal herb) makes it interesting to keepers who also grow Brahmi for tea or supplements, though the submerged aquarium form is not typically harvested for herbal use. Hardy, forgiving, and a good beginner plant. In outdoor setups and ponds in warm climates (USDA zones 8+), Bacopa monnieri grows as a marginal plant in shallow water or damp soil, flowering prolifically. The plant can become mildly invasive in wet, warm environments, spreading through creeping stems. In the aquarium, growth stays contained and manageable. Widely available from both aquarium retailers and herbal/Ayurvedic plant suppliers.

Further reading

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