Marimo is a unique type of algae, specifically a form of Cladophora, that grows into round, green balls. These aquatic plants are typically found in freshwater lakes, particularly in Japan, Iceland, and Scotland. Marimo thrives in cool, shallow waters and can grow up to 12 inches in diameter over many years. Due to their distinctive appearance and low maintenance needs, marimo are popular as decorative houseplants. They are often kept in glass containers filled with water, where they can continue to grow. Marimo is also considered a symbol of good luck and longevity in some cultures, making them a cherished addition to homes.