Well, there are flame scallops, turkeywing clams etc. They require feeding phyto plancton and can be a bit of a pita to keep alive. You might also come across some hitchiking clams etc on your live rock. They require farily constant feedings of foods like marine snow and phyto plancton. You could also add featherdusters and similar aneliads as they will like a similar envriornment. It won't be easy and some like the scallops don't live very long in the wild even. The turkeywings are fairly hardy and sometimes even make it in tank without supplimental phyto. The thing is they look like rocks so there won't be much visual intrest. There is also a fairly pretty oyster that is imported from time to time but, it's name escapes me at the moment.
Hth
Max
Hth
Max
