Originally Posted by Proflooney
the mossball does something in the aquarium I cant remember atm I think it just helps absorb more ammonia from fish waste. it will sit at the bottom and when it gets hungry and needs more light it will float to the top of the aquarium for a while and then when it is full will sink again.
That's actually exactly what I heard from a lady at petsmart when a customer asked about them.
They don't get hungry and float to the top to collect light. That's just an action of the flow in the tank and at the very most a possible buildup of o2
inside the moss ball from it absorbing some co2
in the tank.
The moss balls are algae and the thing that keeps them round is water movement. They will need to be rotated occasionally or the bottom layer will die from lack of light. They are neat and won't hurt anything to put them in your tank.