No idea what this is...

[iannarelli]

So I noticed this thing on one of my hammer coral frags that is very well camouflaged and reacts to light. It appears to be "inflated" and then deflates/flattens against the coral when light shines on it. I captured a video which I'll try and upload here since it's short, but it's also on YouTube:

 

[PharmrJohn]

Wow. I have no clue. I managed to pause at the right moment but there's just not enough detail.

 

[Slocke]

@ISpeakForTheSeas

 

[iannarelli]

Wow. I have no clue. I managed to pause at the right moment but there's just not enough detail.

I can try to take a video on a tripod with my mirrorless and upload that if it will help.

 

[iannarelli]

Higher quality video here:

 

[ISpeakForTheSeas]

Higher quality video here:

That's a bivalve of some kind (Bivalves include clams, oysters, mussels, scallops, etc.) - it's a harmless filter-feeder and shouldn't hurt the coral at all.

 

[krissiRLT]

I agree it looks like a bivalve and shouldn’t be harmful.