Most foreground plants are not too difficult to grow given enough lighting, CO2, and nutrients.
Glossostigma elatinoides comes to my mind as the most ubiquitous foreground plant. Grows rapidly, forming a short, dense carpet. High maintenance.
Marsilea quadrifolia is similar to glosso but it is *slightly* slower growing and does not require as much light. Nice, waxy, deep green foliage.
Eleocharis parvulus is nice for a very fine, grassy look. It does grow rapidly but doesn't seem to need as much thinning as glosso. Eleocharis acicularis is a suitable alternative.
There are many others, but these are the ones I have most experience with...
Carlos |