Clams....Why Sand??

I bought a new deresa clam (3-3.5" or so) I have read they go on sand. I have also read to put rock under sand for them to attach to or they may attach to bottom of tank or also to keep bristle worms, etc out of them.

If you put rock under sand for them attach to, why not just put them on rock in the first place??

Thanks !

 

Some clams bore into the rock such as crocea and maxima clams. I don't now if dersea clams do too. It may be because they don't bore into the rock, they just attach themselves to the rock with their foot.

 

Should I have a rock under the sand for him to attach to?

 

If your sand isn't too deep, it should be able to attach to the glass aquarium bottom. That being said, I'd rather have it attach to a small piece of rock or shell so that if you need to move it, you can just pick it up and do so instead of worrying about cutting its byssal threads.