Just wanted to throw my 2 cents in to stay away from "Condy" anemones. Clowns will not host in them (or pretty much anything else ... there have been reports of damsels hosting in them) ... in fact, the condy will eat them.
If the clowns are new to your tank, give them time. I have a skunk clown that does not host in anything and is happy. Over time, your clowns might pick a coral to try hosting in. This can be good or bad, as sometimes they can be a bit overly agressive in hosting a coral and really bother them.