Something is growing on the underside of this rock...

[Necropotence7]

Any idea what this stuff on the bottom of my rock is? It looks like mold.

 

[7of9]

I'm gonna guess some kind of sponge. If it were me, I might pull the rock out, put it in a bucket of RO/DI, and scrub the sponge off with a toothbrush if it seems to be spreading

 

[TangerineSpeedo]

Sponge... Sign of a healthy aquarium. That type usually doesn’t like light. Filter feeder

 

[Necropotence7]

I'm gonna guess some kind of sponge. If it were me, I might pull the rock out, put it in a bucket of RO/DI, and scrub the sponge off with a toothbrush if it seems to be spreading

Thanks for the help. It hasn't been spreading so I'll just keep an eye on it. I've got my hands full with Vermetids right now anyways