Waterspite
This plant float on top of the water but it can be planted. It need a fair amount of light to grow good.
Java Moss
This plant grow quite fast and it will do very well with low light. It have no roots but it will attacted itself to what ever it find. It also like to clog your intake pipe on your power filter.
Duckweed
This aquarium plant will grow very fast, if it get enought light. In my aquariums it double itself every day.
