Mermaid’s Fan (Udotea flabellum)

The Udotea Plant, also known as Mermaid’s Fan or Udotea flabellum, is a popular aquarium staple composed of calcareous algae. It features a broad, fan-shaped top that is dark green and can grow up to 12 inches or more. The plant is anchored upright in the substrate by a group of rhizoids. These rhizoids, with a large base, can extend several inches below the substrate, allowing “shoots” to grow from the parent colony and produce new plants.

This species reproduces rapidly in aquariums by establishing new plants close to the base when conditions are favorable. It requires a deep sand bed of at least 4 inches, as it grows only in the substrate. To achieve maximum growth, which can be up to 1 inch per day, calcium supplements are necessary. This aquatic plant is inedible to fish and other invertebrates, making it a durable and attractive addition to your aquarium.