Chroomonas virescens is a species of cryptophyte alga in the family Chroomonadaceae, characterized by a greenish coloration, as reflected in the specific epithet virescens, meaning becoming green. This greenish hue distinguishes it from many Chroomonas species that display blue-green to brown tones, suggesting a particular phycobiliprotein composition or a balance of chlorophyll to accessory pigments that shifts the overall color toward green. Cryptophyte algae display a wide range of colors depending on the dominant phycobiliprotein in their plastid: phycoerythrin-rich species appear red to orange-brown, while phycocyanin-rich species tend toward blue-green or olive tones. Chroomonas virescens has been documented from European freshwater habitats. Like other Chroomonas species, it is a small, biflagellate, planktonic or periphytic unicell that contributes to primary production in its aquatic ecosystem. Freshwater cryptophytes perform an important ecological function as cold-tolerant primary producers that can be active during periods when many other algae are dormant. The species has not been assessed under IUCN conservation criteria.