Pearl weed

Quick facts

Max height

30 cm

Growth rate

fast

Difficulty

intermediate

Placement

foreground, midground, background

Propagation

cuttings

Water parameters

Temperature

20–28°C

pH

5.5 to 7.5

Hardness

1 to 12 dGH

Light and nutrients

Lighting

medium

CO2

not required, but boosts growth and color

Substrate

nutrient rich

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 Cuba, the Caribbean, and parts of Central and South America. The species (Hemianthus micranthemoides, sometimes sold as Micranthemum micranthemoides) is a small-leaved stem plant with tiny, oval, bright green leaves (2–4 mm) arranged in whorls of three around a thin, upright stem. The plant forms dense, bushy masses when grown in groups and trimmed regularly. Pearl weed has gained popularity as both a midground filler and an alternative foreground carpet: when trimmed very short, it produces a lawn-like carpet, and when allowed to grow taller, it forms a dense, bright green bush. This versatility is the species' main appeal.

Care notes

Easy to moderate. Grows under low to high light, with or without CO2. Under high light with CO2, growth is fast and the plant can be trimmed into a tight foreground carpet (1–3 cm). Under moderate light without CO2, it grows as a bushy midground plant (5–15 cm). The transition between carpet and bush is controlled entirely by trimming: cut short for carpet, let it grow for bush. Plant stems in groups, pushed into substrate. Growth is moderate to fast under good conditions. Trim frequently to maintain the desired shape; the cut stems produce abundant side shoots, creating increasingly dense growth with each trim cycle. The small leaves and fine stems create a soft, bright green texture that works as a filler between larger-leaved plants and hardscape. Temperature: 20–28°C. pH 6.0-7.5. Soft to moderately hard water. Nutrient requirements are moderate; liquid fertilizer keeps the bright green color. Without nutrients, older leaves yellow and drop. Pearl weed is one of the more versatile aquarium plants because it can fill multiple roles in the same tank depending on how it's trimmed. Available from aquatic plant retailers. Compatible with all community fish and shrimp. The dense growth provides excellent shelter for fry and grazing surface for shrimp. A very practical plant that fills gaps in the aquascape and serves as a living background or carpet depending on maintenance approach. Widely available from both retail stores and hobbyist trades.

Further reading

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