Marimo Moss is a rare type of living green algae that's native to Japan. They get their round shape from rolling across the bottom of lakes with the tides. Marimo Moss are considered good luck and a symbol of everlasting love. They make a great low maintenance pet!
To care for the Marimo Moss simply change water every two weeks. Keep them in low lighting (away from direct sun) and under 78 degrees. Your Marimo prefers dechlorinated water, and an easy way to condition tap water is leave it at room temperature for 48 hours. Put your moss ball in the fridge to cool down on a hot day or as a treat for it! You can even periodically roll the algae gently between your fingers or swirl it in the water over the aquariums rocks to help the moss keep it's round shape.
Marimo sink or float because of oxogen produced during photosynthesis. On occasion, you can sprinkle a bit of sea salt into the water to perk up the algae and run them under cool water and and gently squeeze if they start to look brown. Marimo Moss grows about a half a centimeter a year, and can also be propegated by dividing a piece off a bigger one and rolling it into a new ball. This happens in the wild when they get too big (over 100 years!) for clean water to get to the core. At that point the moss ball breaks up and rolls into new moss balls.