Oh! Oh! Wait! I have an opinion on this one. Wait until you introduce an external parasite, such as a fluke, into a tank with your other cherished fishes. I have had this experience, and let me tell you something, brother; it is much easier on both you and the fish(if your dipping correctly) to dip the fish before, than have to catch him, and potentially others, in an established reef tank. If you haven't had this pleasure, or rather displeasure, I highly recommend avoiding it!
For those advocates of the "well kept system=no parasites" theory, I say this. Your half correct in the assumption that a healthy system helps prevent disease, but your also half lucky!