Gray Sponge

[sketh]

Any idea what these gray looking splotches are on my rock? The left-most one seemed to have moved from underneath another rock- possibly some kind of invert?

 

[Dburr1014]

Any idea what these gray looking splotches are on my rock? The left-most one seemed to have moved from underneath another rock- possibly some kind of invert?

Where did the rock come from?

Left almost looks like a mushroom, idk.
The others look like sponge.

 

[sketh]

Where did the rock come from?

Left almost looks like a mushroom, idk.
The others look like sponge.

It’s live rock bought ~60 days ago. I did a fishless cycle so any sponges/critters on the live rock should be dead AFAIK

 

[ISpeakForTheSeas]

Any idea what these gray looking splotches are on my rock? The left-most one seemed to have moved from underneath another rock- possibly some kind of invert?

Sponges would be my first thought, but not many sponges move. Do they all move, or just the one on the left?

If it's just the one on the left, it's possible that you could have a sponge-mimic snail or nudibranch, but those are very rare in the hobby.

 

[sketh]

Sponges would be my first thought, but not many sponges move. Do they all move, or just the one on the left?

If it's just the one on the left, it's possible that you could have a sponge-mimic snail or nudibranch, but those are very rare in the hobby.

The sponges actually haven’t moved- I think it was a blackish Asterina I saw and thought it was the sponge.

I think the sponge is something to do with newer live rock bought from LFS. I’ve seen several other people with the same gray splotches as I who say it’s just store bought live rock.