Common name: Shaving Brush Alga

General information

Penicillus capitatus, commonly known as the Mermaid's Wine Glass or Green Finger Plant, is a distinctive species of algae found in the marine aquarium hobby. It belongs to the family Udoteaceae and is notable for its unique, cup-like shape that resembles a wine glass. This calcareous green alga is not only visually appealing but also plays a role in nutrient export, helping to maintain water quality by absorbing excess nutrients like nitrates and phosphates.

Care

Caring for Penicillus capitatus requires a stable marine aquarium with adequate lighting and water flow. It thrives in environments with moderate to high lighting and benefits from the addition of calcium and other trace elements to support its calcareous structure. It's important to anchor it in the substrate to prevent it from being dislodged by water movement or the activity of other tank inhabitants.

Symbiosis

While Penicillus capitatus does not have the same kind of symbiotic relationships as some corals or anemones, it does provide a microhabitat for small invertebrates and can contribute to the overall health of the reef tank ecosystem by competing with nuisance algae for nutrients.

Habitat

In the wild, Penicillus capitatus is found in shallow, sandy areas of tropical and subtropical seas, often forming meadows that provide shelter and food for a variety of marine life. It is commonly found in the Caribbean Sea and the Gulf of Mexico, where it contributes to the complexity and productivity of these ecosystems.