I agree with both Kevin and Micheal. Take my clown for instance. I have had my Spine-cheek for about three years now. When I got him I also bought a H. magnifica anemone. He ignored the magnifica like the plague. He finally took up in a colony of Anthia when the colony grew to his liking (check him out in the Jan pic contest). As for the magnifica, well he has thrived, grown to approx 14"-15" in diameter. The clown has also thrived....grown to at least 3" in length. I also did some homework and learned if your trying to match clowns and anemones make sure you find out if they come from the same region. If they don't they most likely will never take up a relationship. On the other hand they can be from the same region and still not take (possible, but not likely). In the end it's all up to nature and the animals.
But hey, that is is one of the greatest things about this hobby....the learning!
Good Luck with your clown and anemone.