there are 3 natural hosts for ocellaris clowns. Unfortunately 2 of them are very difficult to keep (or get a good one), and the 3rd is rarely imported (gets huge). Those anemones are
H.magnifica. (difficult)
S.gigantea (difficult)
S. mertensi (rare)
Having said that, clowns dont need their "natural host" I have paired many clowns with un-natural hosts.
I think the most striking pair (trio) is some black ocellaris in a really nice rose anemone (AKA RBTA) AKA E.quadricolor