Pearl weed
Micranthemum micranthemoides
Also known asBaby tears (small leaf) · Hemianthus micranthemoides
Water parameters
Light and nutrients
Substrate type: nutrient rich. Propagation: cuttings.
Substrate compatibility
| Substrate | pH effect | Nutrient load |
|---|---|---|
| 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 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.