I would just add that this is a very slow-growing plant, so don't be wondering why it isn't spreading readily. Growth will be slow under moderate light; with brighter lighting and additional nutrient supplementation including CO2 diffusion growth will be faster. This plant will only form truly thick "carpets" with high light and CO2.
I will also mention another similar plant that might work if this one doesn't, and that is pygmy chain sword. This looks much like Lilaeopsis brasiliensis (micro sword) but it not in the same family. The correct scientific name of the pygmy chain sword is Helanthium tenellum, but you may still encounter it under Echinodorus tenellus as it was reclassified recently (2008 I believe). This plant grows larger, from twice to three times the height, but it is certainly very tolerant of moderate to even low-moderate light, and does not need CO2 to form thick carpets, and I do mean thick. I'll attach a photo of this species along the front (and everywhere else) of my 70g before I severely pruned it back. I have successfully grown this plant in all of my tanks under various lighting and with the addition of a complete liquid fertilizer such as Flourish Comprehensive Supplement, and in sand or fine gravel.
Byron.
/www.wikihow.com/Cultivate-the-Micro-Sword-in-Your-Aquarium 
