2 questions: ID and when to add a clown

[Rebel]

I added a "carpet anemone" to my 180 reef two days ago. I had a cove built for it and researched a bit (probably not enough) before hand--and I found what looks like a really healthy anemone. It is about 12-14" across and a lightish green. It was marked as a "Columbo" at the LFS. I had anticipated it burying its foot into the sand, but it attached to a small rock instead. I don't have a pic, sorry, but does someone know where I could view pics to try to get a scientific ID on this?

Also, how long does one usually let the anemone get established before adding a clown? Of course, I will have to research that too--which is why I need to know the exact species of anemone.

Thanks for the help.
Jason

[Rebel]

I finally found TRA vol 2 (there was nothing in TRA vol 1).

It appears that is is a S. haddoni, as I initially thought. Its tips are very short and smooth. However, as I mentioned it has attached to a small rock rather than burying itself in the sand (I have about 4" DLSB). Has anyone known theirs to do this? TRA mentions they are "most common in sand, gravel or mud in shallow water" (403). I guess that doesn't rule out one on a rock, and they mention it is possible.

What are some favorite clowns kept with these? Any suggestions?

Thanks,
Jason