Euglenoids are unicellular flagellate protists commonly found in freshwater ponds, pools and moist mud. Though the euglenoids are photosynthetic in the presence of light, when deprived of sunlight they behave like heterotrophs by predating on smaller organisms (holozoic) or feeding on organic remains (saprobic). Such a mode of nutrition is called mixotrophic. Photosynthetic pigments of euglenoids are identical to those present in higher plants, e.g. chla and chlb.