Weird looking 2 part shell snail?

Was looking around the tank at night and noticed this thing climbing very slowly up the back wall, dunno wth it is, I've seen them hidden in the rockwork before but I just always though it was some kind of scallop or clam cause of the shell shape but this one is climbing like a snail but very very slowly

 

update, I pulled the bugger out and put him in a cup of water from the tank until I can figure out wth he is, figured it was as good of a time as any to make sure he doesnt harm anything

 

Hi Iraf,

That's actually a clam in the family Arcidae, probably Acar plicata.

Conchology, Inc - Search Results - ARCIDAE

As you've noticed, they can actually climb and crawl like a snail, an advantage if you're a clam and your nice hiding place gets to be not so nice. These usually live under rocks in clean white sand, right at the surface (not buried), in areas that are devoid of most other marine marine life. It should be a harmless filter feeder, and a neat find for your aquarium.

Cheers,



Don

 

Cool, thanks Back in the tank it goes then, hopefully it hasn't been harmed by it's taking out of it

 

Cool- I was just about to write a post about a similar bivalve-looking thing I found on the back side of my bubble last night. Mine is ~1cm long, and appears "hairy", although that may be algae on the shell.

 

I have some stomatella varia in my tank actually, weird little creatures and only out at night, came in as hitch hikers and from what I've read their actually a good thing to have.

I put the little clam back in last night, as of this morning he had moved back to the front of the rockwork

 

Hey Geej,

That's actually the periostracum on the shell, most likely, rather than algae. Sometimes Acar plicata has a bit of the hairy, leathery coating remaining, but often it's missing entirely. However, some of the closely-related species in the family may have from half the shell covered to the entire shell covered with the hairy periostracum. Some of the shells on Poppe's site (linked in my above post) still have the periostracum remaining, or you can Google search for Arcidae and see a lot of the other "hairy" shells.

Cheers,



Don