The only way to prevent aiptasia is:
1. Do not bring "live" rock and/or "live" substrate into your system.
2. Do not bring any living organism (coral) attached to a piece of rock into your system.
3. Do not allow any amount of water from another tank to enter your system as an aiptasia spore may be present.
This basically leaves only fish and some inverts (I have seen aiptasia on a snail). Kind of narrows it down allot, doesn't it!?
As far as cures are concerned, there are many methods which have been used, some more effective than others in ridding this nasty pest, albeit none are guaranteed to exterminate aiptasia 100%.
Good luck with your present situation. I wish you success.
