This plant grows super fast!! I have had in in my 20g tank for 3 months now and it has covered about 1/3 of the bottom of the tank. It is still very dense in the spot where I originally placed it. It has sent out so many runners that I am starting to see it poking through the substrate almost 1.5 feet away from the main mass of the plant. I have a very fine sand substrate so I think that that definatly helps the plant reproduce rapidly.