A large green polyp'd toadstool, surrounded by GSP. Think of it looking like a beautiful tree and gsp being grass. Not even kidding this honestly could be really gorgeous. Line the most amazing arrangement of zoa's coming up the arches, and just use the whole sanded covered in euphyllia.
How long has the tank been running? I would not put a clam in with that flame angel.
This setup was originally in my biocube about 5 months. I just transferred it to the new tank about 3 weeks ago. I haven't looked into clams but to be honest they don't really spark my interest and don't think I'll be adding any.