It's not hard to understand why Chaetomorpha is also called green hair algae. This thready seaweed looks like spools of dull green transparent ... hair. If you look closely, you can see rows of cells, even with the naked eye. There are many members of the Chaetomorpha family. Some grow from a fixed base, others grow while floating. During the summer, the tidal flats can be covered with large masses of Chaetomorpha. Although it seems to suffocate everything lying underneath, it also offers protection to gammarids, shore crabs and laver spire shells. Chaetomorpha is used in marine aquaria to filter the water. It converts nitrogen wastes produced by the fish into plant food!