Monte Carlo
Micranthemum tweediei
Also known asMicranthemum 'Monte Carlo' · Tweedie's micranthemum · Baby tears (trade)
Water parameters
Light and nutrients
Substrate type: nutrient rich. Propagation: fragmentation.
Substrate compatibility
| Substrate | pH effect | Nutrient load |
|---|---|---|
| Aquasoil (ADA Amazonia) | lowers pH | very high |
| Mineralized clay substrate (Seachem Fluorite) | neutral / inert | moderate |
| Inert sand (Pool filter sand) | neutral / inert | none |
With fish
Origin and habitat
A low, creeping carpeting plant of the family Linderniaceae, Micranthemum tweediei, native to the southern cone of South America in Argentina and Brazil, growing in wet, rocky riverbanks and shallow water. It entered the aquarium hobby around 2013, collected near the Monte Carlo municipality in Argentina, which gave it its trade name; for a while it was mislabelled 'Bacopa sp. Monte Carlo', but it is a Micranthemum, not a Bacopa. It makes small round bright-green leaves 3–5 mm across on creeping stems that root at each node, forming a dense low carpet. It carpets more easily than HC Cuba at a slightly larger leaf size and has largely replaced HC as the default intermediate-level carpet.
Care notes
The most practical carpet for medium to high-tech tanks: easier than HC Cuba, faster than Marsilea, and denser than dwarf sagittaria. Moderate to high light, roughly 50 to 100 PAR, and CO2 give the tightest, lowest carpet, but unlike HC it does not strictly need either, and many people grow it without CO2, just slower and a little taller. A nutrient-rich substrate such as aquasoil feeds its vigorous roots. Plant small portions from tissue culture, each with leaves and roots, a couple of centimetres apart, and a carpet closes in four to eight weeks. Trim with scissors to hold a height of 1–3 cm, which pushes horizontal creeping and density; if gas bubbles lift the mat off the substrate, press it back down. Keep it around 20–26°C in soft to moderately hard water. Algae is less trouble than with HC because Monte Carlo grows faster, but balance still matters. For most aquascapers it delivers most of HC Cuba's look for much less of the difficulty. It is an ornamental carpet, not a crop, so it is unsuited to media-bed aquaponics or hydroponics.