round white mass under zoa plug

[gmerfbox]

Can't tell what this white mass is under my zoas, any ideas? I couldn't match it up with the common hitchhikers on the sticky posts...

 

[TheBear78]

My best guess would be a sponge.

 

[Tired]

If it doesn't respond to being poked with something, it's likely a sponge. Some sponges can irritate corals if they spread overly far, but most are harmless.