Is this a clam on my coral?

[Hiward]

I’ve had this Hammer cCoral for about 4 months now and always noticed this calcium thing growing, but thought it was just branching off. But the other day I saw it move and it’s growing bigger and killing my hammer coral. What do I do? What is it?

 

[formallydehyde]

Can you pull the frag out and get a closer picture?

 

[Hiward]

Can you pull the frag out and get a closer picture?

 

[ISpeakForTheSeas]

It's definitely a bivalve of some kind (bivalves being things like clams, mussels, oysters, scallops, etc.). Bivalves are harmless filter feeders, so I wouldn't expect it be causing any problems (so I'd be looking at other potential causes for the hammer coral's decline).

That said, if you're worried that it's causing problems by growing so close to your coral, then I'd see if you could remove it and put it somewhere else on your rocks.

If the bivalve is growing well, then you may not need to do anything to help it grow, but I'd guess some dosing of Isochrysis galbana and/or Chaetoceros sp. would be appreciated by it too.

 

[Stephen8169301]

Definitely looks like a clam you can see mouth open an close in video

 

[Hiward]

Definitely looks like a clam you can see mouth open an close in video

The clam is growing on my hammer coral’s skeleton

 

[EeyoreIsMySpiritAnimal]

Unfortunately, and likely not due to the clam, that hammer is at death's door... sorry.