Marimo Moss Balls - For Your Aquarium or as a Pet
Often sold as a plant, the Marimo moss ball is really a filamentous green algae. Moreover, it is just a particular rare growth form of the Aegagropila linnaei. It is quite spongy and different from the java fern moss balls that some aquarium shops market as moss balls. Java fern balls do not grow in the shape of a ball, but is just the regular java fern wrapped around a circular object and are completely different. If you buy these they are not going to stay circular and you would have projections of fern fronds all over.
This page only discusses the Marimo moss ball and the message about some shops selling java fern in its place is to serve as a warning to those new to the hobby. Furthermore, most of you visiting this page are probably looking for a moss ball for your aquarium, but there are plenty of people who keep them as a pet on their own in a tank, a jar or some other container. Here you will find a lot of helpful articles that covers both these aspects, not that there is a real difference when it comes to the care, propagation, etc. of your Marimo moss balls.