Image is just a representation. This is for an assorted Green Colored macro algae. Caulerpa is a type of green algae, or a genus of seaweeds from the Caulerpaceae family. They are unicellular organisms with multiple nuclei, which make them one of the biggest single-celled organisms worldwide. To ensure an easy identification across the Mediterranean reefs, it outgrows a stolon which can be 3 meters (or up to 9 feet) long and has 200+ fronds. A common introduction in the Aquarium trade, Caulerpa is used for absorbing nitrogen inside a closed chamber. With a great ability to grow under harsh, challenging conditions, Caulerpa is also used as a long-term nitrite absorber in refugiums. They proliferate asexually from spores by fragmentation. The aquarium water generally turns milky-green during this process. These spores can be later sieved out or left in the tank (which may settle down over time). However, this marine alga leaves a soft white-tissue husk that has to be removed after some time. These are the natural habitants of warm waters and reefs of the Northwest Hawaiian Islands.