euglena sanguinea euglena sanguinea euglena sanguinea is a species of the genus euglena. the red colour is due to the presence of astaxanthin and the cells can be populous enough to colour water red. the pigment is used to protect the chloroplasts from light that is too intense, but as the light levels change the cells can take on a green colour as the red pigment is moved to the centre of the cells. euglena sanguinea is known to make the potent icthyotoxin euglenophycin. euglena sanguinea scientific classification domain: eukaryota (unranked): excavata phylum: euglenozoa class: euglenoidea order: euglenales family: euglenaceae genus: euglena species: e. sanguinea binomial name euglena sanguineaehrenberg, 1830