Marimo

algae · rare · spheres · freshwater

Fuzzy green spheres. Marimo are made of a special kind of algae called Aegagropila brownii that grows into giant balls instead of spreading out like normal algae. They feel velvety soft on the outside.

Found in few places. Marimo are extremely rare and grow naturally in only a handful of freshwater lakes in the world, especially in Japan where they're considered a living national treasure.

Super slow growers. A marimo ball only gets about 5 millimeters bigger each year, so even a grapefruit-sized one could be hundreds of years old.

Move with currents. Marimo balls gently roll around lake bottoms pushed by water currents, and this movement helps them grow evenly into perfect spheres from all sides.

Cultural symbols. In Japan, marimo are so beloved that people keep them as pets in special glass bottles, and they're displayed in museums as living art.