What is this in my acan?

As the title says can you tell me what it is if you touch it it will go back in
oh and the white is food I was feeding the acan


If you look to the top right you will see another one with a side view and I touched it and you can see it kinda closed up


What is this in my acan? - The Reef Tank

 

That's werid, you got me. Looks like some kind of clam or something of that nature.

 

it does look like a clam to me also. How long have you had the acan....is it growing well? Problem with acan is if when you frag them they dont do very well and you can end up loosing a bunch. So I would say keep an eye on it and see how the acans do...if they are fine then I would leave it.

But, I am not sure so if someone can chime in...

 

I would say a type of bivalve!

 

I agree with CR

 

does it have an arm that comes out and sweep the tank.

 

a bivalve of some sort, if your acans start to go downhill they might be the cause, keep an eye on them