Here's a good reference for which species of anemone host which clownfish. Clownfish can be very rough on other non-anemone invertebrates and actually kill them trying to host. If you want to watch their hosting behavior, then get an anemone. Here's a chart from Marine Depot Live. The chart's excellent, but I'm afraid I've had bad experiences with Marine Depot Live's livestock and customer service.
http://www.marinedepotlive.com/IMD/M...s-anemones.jpg