Cyperus helferiCyperus species are widespread all over the tropics, but only a few of them are good underwater plants. Cyperus helferi from Thailand is the first Cyperus species used in aquariums, 20 35 cm tall and a roset from 15 25 cm wide. It requires a relatively large amount of light, and CO2 addition is recommended to promote growth. In aquariums with good water flow the plant sways beautifully in the current.