Spirulina is a cyanobacterium that can be consumed by humans and other animals; there are two species, Arthrospira platensis and Arthrospira maxima.
Arthrospira is cultivated worldwide; used as a dietary supplement as well as a whole food; and is available in tablet, flake and powder form. It is also used as a feed supplement in the aquaculture, aquarium and poultry industries.
The maxima and plaetensis species were once classified in the genus Spirulina. There is now agreement that they are in fact Arthrospira; nevertheless, and somewhat confusingly, the older term Spirulina remains in use for historical reasons.