Hornwort

Ceratophyllum demersum is a rootless aquatic plant with thin, branched stems. Its leaves are whorled, fine and serrated, giving a feathery appearance. It can float freely or be planted in the substrate. Growth is very fast, effectively absorbing nitrates. It provides shelter for fry and invertebrates. In the aquarium, it prefers moderate to high light. No CO2 needed and tolerates a wide range of parameters.