Ceratium setaceum is a species of in the family Ceratiaceae. They are native to Rio Grande Do Sul, Rio De Janeiro, Amapá, Pará, Rio Grande Do Norte, Santa Catarina, SãO Paulo, Paraná, and Espirito Santo.
Definition: Living in the fluid medium (water or air) but unable to maintain their position or distribution independently of the movement of the water/air mass (adapted from Lincoln et al., 1998).