Is this a clam?

[krystinaxlea]

We got this coral a few months back and to be honest I thought this dude was glue or something (I know dumb, I'm still new to salt water tanks) but today I noticed thr zig zags and had been watching closely when I saw it open and close. Scared the crap out of me. All I know is that's not glue. It looks like a clam but I've never seem a clam attached to a coral before. My question is is this a clam and is it OK for my coral

 

[JGT]

Yep, commonly called a bivalve. Harmless to your coral.

 

[ISpeakForTheSeas]

Welcome to Reef2Reef!

Yeah that's a bivalve (taxonomic class Bivalvia, which contains all clams, oysters, mussels, scallops, etc.) - your hitchhiker there is probably a clam or oyster of some kind judging by the mouth there.

Completely harmless and a neat find!

Some do well in our tanks with no intervention, but a lot die out. If yours has been there for months already, then it's probably one that'll do well without help. That said, if you want to try and help it do better, you can try offering it some phytoplankton like Isochrysis (Isochrysis galbana [T-Iso]) and Chaetoceros (Chaetoceros sp./spp.) or a blend containing one or both of those. Like I said, that's probably not necessary for yours, but it may help.