It's depend on how big is your rock.. I am always having fun with killing those thing.. I let the stupid Aiptisia pop out from the hole and quickly remove the rock from the water so that stupid thing won't retreat back to the hole. Then I use super hot distilled water with vinegar and microwave it for 1 min.. distilled water will be mostly far above boiling point I inject the thing with it and it melt and bubbling =) ..then use old tooth brush to brush it off from the rock and rinse it couple of time with old tank water .. I usually wait until when I do water change or cleaning the tank then will hunting down those nasty animal
