Actually aptasia is an anemone. It is a pest anemone. Aptasia X works but make sure you do not do it right before lights out since they release spores more at lights out if you do not get it completely. Peppermint shrimp will sometimes eat them but will eat other food sources also so I have found they are unreliable unless you can stop feeding the tank for a week or so. Copperband butterflies will sometimes eat them. I use a filefish. He does a good job for me but they are hit and miss also. Berghai nudibranches are a sure thing since they only eat aptasia. They are hard to find though and starve when the aptasia runs out