Clams...

[showjyr]

Does anyone know a good type of clam i could keep in my shrimp and snail tank? Looking for somthing kinda small.

 

[three-fingers]

Read these posts:freshwater mussels and clams, freshwater mussels and clams 2 and 3.

After you've read them and you still want one, the clam you'll probably want to be going for is Corbicula fluminea, the Asian clam.
Which is what snailshop appears to be selling here.