Fern Caulerpa (Caulerpa sertularioides)

Fern Caulerpa is a fast-growing species of non-calcified macro algae. Its soft texture means it will be eaten by emerald crabs and algae eating fish but in the absence of these it can be used to quickly liven up a saltwater tank when lighting is not sufficient enough for corals. It is a great indicator for salinity swings as it can be quick to wilt when conditions aren't right.