my case is similar to cybermeez's. aiptasia-x works well for me in my seahorse tank. it does come back every now and then, perhaps a month later?
in my display tank however, the copperband butterfly devours every aiptasia even the ones way inside nooks and crannies:skull::skull:. i even ran an aiptasia elimination service for my buddies. they would bring me their rock/coral and the copperband would chomp on them right before your eyes:biggrin::biggrin:. that's just my case, i also have heard from others that their copperbands never touch their aiptasia.
but unfortunately some copperbands can be difficult to keep. don't really know why. it's more often than not that one would hear a story of how it lasted only a few days/weeks. my first one was in the lfs display for over 6 months, it died the next day in my tank (75 gal). i didn't get the current one until i upgraded to a 270+ gal. system, more than a year later.
it is a bit finicky, besides the aiptasia, it will eat mostly frozen food, the only dry food it will nip but not heartily are freeze dried mysis and small krill. btw it also loves feather duster and coco worm....found that out the hard way:irked: