I have used Filefish also - in the beginning, they seem like they don't do anything or touch the Aptaisia but about 1month, suddenly all the Aptaisia is GONE. Problem now is that they start munching on my Duncans and Frogspawn (i actually witness it), they already kill 2 branches of my Frogspawn, will try to get them out now with a TRAP....
As far as Butterfly, i tried it on my other tank - Kleins Butterfly seem to work better and so far it has not bother my Corals...