White stuff in my rock.

[VicD81]

I've noticed this white growth in a couple crevasses in my live rock. It's soft and only grows in the top part of the caves.

 

[NanaReefer]

Sponge! May or may not thrive. Harmless filter feeder

 

[VicD81]

Sponge really. This thing is huge. It goes from one side all the way to the other side of that cave.

 

[NanaReefer]

Mine covers almost the entire back wall of my tank, behind the rock.
If it's healthy & loving the environment it will grow. Mostly in lower light to very dark areas.

 

[lost02]

Just sponge mine got huge then died off and is now coming back again. They are good for the tank.

 

[VicD81]

Cool Thanks. The things that grow in even the tiniest of environments amazes me!