Cited as “green alien balls” by 7News, better known as Japanese Moss Balls, recently flooded the beach at Dee Why, just outside of Sydney, Australia. Thousands of these small, green orbs, about 2-3 inches in diameter, are actually a form of algae (Aegagropila linnaei). Previously, Marimo balls have been been found in such places as Japan, Scotland, and Iceland, so their presence in Australia has left locals bewildered with amazement.
This type of algae can grow on rocks, or be free floating filaments that coat the floor, but forms the ball shape under certain circumstances. The balls are hollow, completely void of a core, and have been discovered growing up to an astonishing 12-inches in diameter.
The level of care required is minimal, making them excellent additions for aquariums with fish and shrimp, since they only need light for photosynthesis and clean water to thrive. Shifting them about in the tank periodically allows them to stay round and green all over.
(Photo and video credit: 7News Report)