Clowns will host lots of things other than anemonies. I've heard ones even hosting powerheads or even Koosh Balls.
I had one that hosted a starfish. It was very funny watching the clown bring the starfsh food. Never did see the starfish actually take the food, but it sure was fun watching the clown try...now he has adopted a brain coral I have. Same deal, though, the brain coral does not take the food.
I guess neither the starfish or the brain coral are properly equiped to take food in that manner, they need much smaller chucks and don't want them waived in front of them by a clown!
I kind of feel sorry for the little guy!