Marimo Moss Balls
These fluffy green balls are actually a rare form of spherical algae. There's no center to them, just algae growing outward at about 5 mm a year; in its natural habitat, marimo can get up to 12 inches in diameter. They only grow naturally in a few fresh water lakes in Japan, Estonia, Iceland, Scotland, and Australia. These little plants can live over a hundred years!
These guys are naturally used to low light and cool water, so they need to be protected from any direct light. They'll happily photosynthesize in normal household light, or close to a fluorescent or full-spectrum bulb.
Change the water in its vessel every two weeks with regular tap water - for best results, let the water sit overnight before introducing the marimo.
If your marimo is turning brown, it's more than likely receiving too much light or its water is too warm. Move it back to a cool area with less direct light and it should bounce back.
Marimo balls are rolled across the bottom of lakes by gentle waves, giving them their round shape. Keep yours round by gently shaping it in your hand and agitating its enclosure from time to time so it rests on a different side.