Ceratopteris thalictroides isn't all that normally grows fast but with the addition of CO2 it really motors. In a small aquarium it can grow out of the top and form truly wonderful and decorative leaves. The fine branches of the leaf itself are decorative and provide an interesting contrast to other types of leaf shapes.
In good light Ceratopteris thalictroides grows very fast and helps to prevent algae by consuming large amounts of nutrients. As a result this is an ideal plant for beginners with small aquariums.