Just to make the point clear, I would not put a mandarin in a tank with a bta, even though it would be a considerably smaller risk than a mandarin with, say, a carpet, which would eat it quickly, no doubt. I am only saying that the time it would take to catch the fish might be considerably longer with a clown hosting. Due to the constant foraging activity of mandarins, the fish will come into harms way more frequently than most fishes. To place the fish in this situation would be viewed by some as irresponsible husbandry, others may make the distinction that certainly an anemone has eaten a mandarin (and all kinds of other fish, for that matter) a time or two in the wild, and that reef aquariums should reflect a natural analogue of this environment. Whatever your particular stance concerning this situation is, keep in mind that your fishes' days may be numbered, and don't be disappointed when he turns up MIA. Good luck, maybe you could update us, many reefers have kept these two beauties together for years, and I am hoping for the best.
Joey
Joey