What kind of clam?

Discovered this funny clam in my tank "glued" into the ls and wonder which sort it is?

 

looks like a normal clam to me, is it alive?

 

Yes, it's alive. Open and close its mouth

 

Almost looks like a slipper oyster type.

Hopefully pagojoe will see the thread.

Are there two shell that come together when it closes?

 

It looks more like it's parted with the living stone and that's the other "shell". And close to its mourh it has like small "teeth" when it's open.
Here's a better pic

 

I suspect it's an oyster and harmless. I believe what appear as teeth are gills or the mantle.

In tanks that to not run a low nutrient system, feed frequently and introduce some fine particulate matter into the water column the mollusk might live for a good deal of time. In todays low nutrient and high filtration systems you probably need to make a concerted effort to provide the right nutrition to keep it alive long term.

 

Wow, that's cool for sure but what kind could it be?
Thanks for answer!

I'm from Sweden btw

 

I wonder where you rock originate from, do you know?

Is this your first tank set up?

 

We were never told where this come from, but where do you think? This new rock looks much different than the first ones we bought.
This is our first saltwater tank, JAD 128 with 33 pounds ls from 2 different stores.

 

That is a great start.

The rock looks like real reef rock, so any tropical or sub tropical locations. I image you guys probably get the majority of your LR from the Indo Pacific, but I could be complete wrong.

Here is nice little link to help you make ID in the future. There will be some creatures that some how find there way into everyone tank eventually, most are harmless.

Live Rock Hitch Hikers