Clowns and Fake Anemones'/Arrow crab and clown's

[Clown]

Will Clown fish use fake anemone's?
Oh and was also wondering about a arrow crab eating these clowns
there small mabey 1.5-2 inch's and the crab is about 7 inch's from tip of leg to tip of leg (about the size of my hand)
and the clowns seem to be hanging around the crab,
Should i be worried about these clowns becoming a light snack?