Mermaid's Fan species (family Penicillus) are a single stem plant with wide leaves. It looks similar to a folding fan. These are anywhere from 3-8" tall, and will have a full root section. Can be planted in the main aquarium, as fish typically don't snack on them. They do like a broad spectrum lighting with moderate flow, and the root ball needs to be buried in sand. They are a great addition to any display tank or refugium. As with most macro algaes, these are great at reducing nitrates and phosphates. They will benefit from calcium and iron supplements.