Clam, Oyster?

[Marcusa]

I noticed this the other day in my tank. When the rock is touched it moves like it is closing. The picture is what I assume the animal uses to filter feed. When the rock is touched the opening retract and the animal closes. I am just not sure what it is.

Marcus

 

[HovaRockz]

Can't see to well very blurry

 

[NarwhalLover3]

Looks to definitely be some type of bivalve

 

[Djsilentchild]

Sounds like a clam... Can't tell from picture... I was going to get one the other day but my tank isn't old enough..

 

[Marcusa]

Here are some better pictures of the bivalve.

 

[Djsilentchild]

Def looks like a clam... But I'm new to the hobby so I'm not 100% sure..

 

[Marcusa]

I was thinking it was an oyster because of those yellow things sticking out, but not sure at all.

 

[Armoredspider]

I'm pretty sure it's an oyster because it has no lip. It looks sort of like a thorny oyster to me. If it was a clam then it would also need high lighting to be opened up so I assume it's an oyster.