Yup the feathery stuff is Cabomba... It takes a long time to root and will need something to feed on, also it requires very high light... but once it starts growing it looks GOOD! And fills space well. The key is to give it enough light to actually get growing. There is a red variety of this plant also, which is even more demanding in regards to light, though both are easily kept otherwise.
You should consider some Cryptocoryne, they come in a huge variety and like low light. I used to collect them
Though I would plant them somewhere that will be quite shaded, or where taller plants will keep any bright light off them.