Marimo are unique, spherical green algae that form in freshwater lakes, particularly in Japan, Iceland, and Scotland. They are composed of a type of green algae called Aegagropila linnaei, which grows in a fluffy, ball-like shape. Marimo thrive in cool, shallow waters and can live for many years, sometimes even decades. These fascinating organisms are often kept as pets in aquariums or as decorative items in homes. Marimo are not only visually appealing but also contribute to the ecosystem by providing oxygen and serving as a habitat for small aquatic creatures. Their popularity has led to conservation efforts in areas where they are naturally found.