House of fins in Greenwich, CT employs some professional aquarists with incredibly impressive resumes. One of those was Ken Wingerter - marine scientist, author, marine ornamental fish beeeder, and jack of all trades in the science and aquarium fields.
While working together at HOF, I learned a few new things from Ken. One morning I was putting together a fish order from Florida. Ken turned to me and said, "see if they have molly millers. They eat Aiptasia." Why had I never heard this?
Ken explained that when he was working in an aquaculture facility, they had a major outbreak of Aiptasia. But the tanks housing molly miller blennies never had Aiptasia in them.
So we started experimenting with our display tanks. I never actually sat still long enough to witness the molly millers eating an Aiptasia, but the tanks we put them in were clean within the week.
Our maintenance team and customers started stocking their tanks with hordes of these fish. All raved about them.
What could be better Aiptasia control than a small, peaceful, reef safe fish that tolerates others of its own species? They also eat all sorts of algae and have awesome personalities.
Here is Ken's more scientific account of his experience with the molly Miller blenny.