Cryptophytes are single-cell biflagellate algae, with extrusive organelles called ejectosomes. They live in fresh and marine water, mainly in shaded environments where light levels are reduced relative to the surface. They are the product of a secondary endosymbiosis of a red alga, which still retains the endosymbiont nucleus’s reminiscences and has four membranes around its plastids. Cryptophytes have a metabolic diversity that makes them very interesting from a nutritional point of view since they present a balance of fatty acids w3/w6, sterols, carotenoid pigments, and phycobiliproteins, these last also have antioxidant effects. Their composition makes them attractive for food in aquaculture and human consumption, pharmaceuticals and cosmetics; their fluorescent potential has attracted the attention of researchers in genomics, neuroscience and molecular biology. The biochemical composition of the cells is modulated by illumination, available nutrients, and its growth phase. This work reviews the general biology of cryptophytes, emphasizing the photosynthetic ones, culture properties and its biotechnological potential.