Large white bubble sac

[helenjc]

Just noticed this large white sac attached to my live rock from TBS. What the heck is it? Live rock has been in my tank for a few days. It looks kind of like a slightly deflated bubble of a bubble coral but it is attached directly to the rock. It is completely white, no patterns or striations. It’s attached to the back of my rock so I can’t get a clear look at the entire thing but it looks like it’s about 1 inch wide.

 

[NashobaTek]

Picture??

 

[helenjc]

Here’s a video. It doesn’t show much but you get an idea of the movement.

 

[Tahoe61]

Do you have Wrasses?

 

[helenjc]

Do you have Wrasses?

No fish in the tank yet. Just live sand, rock and cleanup crew (hermits, astreas, cucumbers, brittle star, peppermint shrimp). And whatever hitchhikers came with the rocks. But it did come straight out of the ocean so something could’ve laid eggs (or whatever) out there.

I was hoping if it was something bad I could somehow remove it before it hatched/popped but it looks like the sac might now be empty. Gonna go test my water.

Would still like to know what it was if anyone has any ideas.