The Mermaid's Fan plant, a green calcareous algae, is used as a decorative plant in the marine aquarium. These plants have short stems that grow out of the substrate or live rock. These plants form a fan like leaf that is oval to round in shape. They are calcareous algae that deposit limestone (calcium carbonate) in their tissues.
The Mermaid's Fan plant is generally hardy in the right conditions, and few fish will feed on them. In addition to light, they require sufficient calcium to grow. They are not as tolerant of high nitrate or phosphate levels compared to some other algae. They also do not tolerate extensive pruning.