Our yelow long nose butterfly eats aptasia as well (actually just gets a snack from Fliger every once in a while since we don't have any aptasia
). Unfortunately a few other local people have gotten one for this purpose and it hasn't touched their aptasia. Just an idea since it does better in reef tanks than the CB but they seem to be hit or miss on eating aptasia. We also have about 4 peppermint shrimp and they are doing fine for the last 10 months and we never really had aptasia so they will do fine without it.