When my FOWLR became infested with the little annoying Aiptasia
I bought 3 peppermints and a copperbanded butterfly. Worked great,
about 1 week later and not a single one, and i do mean it when i said i had an infestation. All you could see where the aiptasia's. My copperbanded later died about month later, after i found out they have a huge need for lots of food and i beleieve he starved.
The shrimp are still around and i have had a few aiptasia's come back, but where quickly eating by my shrimp. Keep 2 or 3 peppermints in the tank and you will be fine. They will go away. I know how much of a pain it is to inject them, they shrink up so fast. I used boiling water personally to get rid of the huge ones. Also having the peppermints in tank, they will mate and provide fresh food for the other tank mates. GoodLuck