Marimo Moss Balls
Marimo literally translates from Japanese as 'seaweed ball.' Most people think theyre moss grown on a rounded stone.
But these 'moss' balls are actually a rare form of algae that grows spherically!
They're popular in the aquarium world with keepers of invertebrates, like shrimp, that are grazers.
They're about the size of a quarter in diameter, and grow very slowly!
On a scale of 1-10 difficulty, these are a 3 because they prefer to be left alone in a nutrient poor, but high calcium tank. This is often the parameters of invert tanks, which is another reason they're popular in that trade