Hemianthus callitrichoides (HC) 'Cuba' is one of the smallest ground creepers available in the hobby. It is popular as a carpet as its small size makes for a very fine carpet and contrasts well with even other small leaved plants. HC Cuba is notorious for being one of the harder carpeting plants to grow well in the planted aquarium. It is often called dwarf baby tears in the hobby, but this can easily lead to mix-ups as "baby tears" can refer to a couple of other plants as well.
A similar plant that is far easier to grow is Micranthemum Monte carlo, with the difference being insignificant at a distance especially in larger tanks. HC Cuba grows slightly faster than Monte carlo and has smaller leaves and stems. It is not as deep rooted as Monte carlo and requires more frequent trimming. HC Cuba plant requires a lot more CO2 to grow well compared to Monte carlo. Both plants will creep over rocks; but Monte carlo does this more aggressively.
Key Success factors:
Good CO2 levels
Adequate lighting - 40umols at substrate +
Good planting technique - plant separate small strands rather than bunches
Additional points:
Lower temperature helps (< 26 degrees celsius)
Possible to get good growth till 29 degrees or so. Exponentially harder above that. Tanks in the tropics with no chiller should avoid the hassle and just use Monte carlo.
Fine, rich substrates help, but not a necessity (ADA powder)
Not sensitive to KH; can tolerate higher ranges well (10+ dKH
Tissue culture HC can be sensitive to ammonia/raw new aquasoils. Especially using ADA aquasoil, pre-cycle the tank for a couple of weeks before planting to avoid melt completely.
