My current favorite is dwarf Sagittaria, and a photo is at: http://www.cco.caltech.edu/~aquaria/Krib/Plants/Plants/Sagittaria.jpg Mine grow quickly, and have covered every well-lit area (and some not-so-well-lit). They are about 2-3 inches high. I must have 100+ plants by now. I had a small patch of E. tenellus, but the Sags overrran and conquered them. Thank you, Cynthia. Regards, Mark