Common name: Mermaid's Wine Glass

Penicillus is a genus of green algae, commonly known as Mermaid's Wine Glass, found in shallow marine environments. These algae are characterized by their distinctive wine glass shape and are often bright green due to their chlorophyll content. They are calcareous, meaning they contribute to the calcium carbonate structures in the reef. Penicillus species are beneficial in reef aquariums for nutrient export, as they absorb excess nutrients like nitrates and phosphates, helping to maintain water quality. They require moderate lighting and water flow to thrive and can be a unique and functional addition to a reef tank.

1. 
   Common name: Shaving Brush Alga

   Scientific name: Penicillus capitatus
2. 
   Common name: Mermaid's Wine Glass

   Scientific name: Penicillus dumetosus