[Delphinus]

Laurie, I think pretty much any butterfly except for the 2 or 3 reef safe groupings (pyramids and their cousins, bannerfish, and CBB's and their cousins) are going to be a reasonably sure thing for aiptasia .. it's just that when they say a butterfly might anything ... it truly is the case. You never know what they'll develop a taste for. What I've observed of keeping a few butterflies out of that list so far is that tentacles is where it's at. If it's got tentacles, a butterfly will want to sample said wares. Whether they just sample or decimate after that is pretty much a crapshoot.

Even my pyramids, who are mostly plankton feeders, occasionally nip at my two gigantea carpets. That said they leave the maximini alone.

My ulietensis butterfly (had 2 but down to 1 now) will destroy any aiptasia and majano he sees but I had to put him in a FOWLR because he just did too much damage to everything else. LPS, SPS, gorgonians .. only thing he never sampled were clams and again I think this is due to the fact that clams don't usually show tentacly/dangly bits. That said both were model citizens while there were lots of aiptasia to go around and it was easily 6 months before the other damage started becoming evident. So if a temporary arrangement is OK for you (with a FOWLR in the picture after that), I'd totally recommend these as they are awesome fish.

Other butterflies you should look into - Pakistani or redtail, semilarvatus, and yellow long nose. I'm pretty sure all 3 of these will eat aiptasia while being a 50/50 on the "everything else" part. Actually I think the longnose are supposed to be about the same as a CBB, quite safe in a reef usually. Never tried one myself though.

Ultimately, it's a risk no matter what, but it can be a calculated risk.