Natural phytoplankton is an important supplier of energy and nutrients for leather corals and soft corals, shell-fish, and other fine particle filter feeders. PRO-CORAL PHYTON is a well-balanced plankton replacement suitable for all fine particle filter feeders in seawater aquaria. A premium algae blend provides the invertebrates with trace elements and carbohydrates rich in energy in a form only found in the ocean. Spirulina is carotenoid-packed and if combined with brewer's yeast will provide the natural B vitamin requirements and, in particular, vitamin B 12.