This article is a good read.
https://www.liveaquaria.com/article/294/?aid=294
You have to act quick, before one aptasia becomes more aptasia, and there could already be more on the rock you have.
Some could be small and invisible, in the tiny pores of the rock.
Getting Copperband fish, and Pepermints shrimp isn't a guarentee. Berghia do wonders, but they die when no more aptasia since that's all they eat, and they may not get every since aptasia anyway.
If this is your first aptasia in your tank (ie the rock with palys), consider treating outside the tank. What I would call a small Coral QT setup. (or Aptasia QT treatment setup)
The paly's are hardy and get yourself a small container and some water from your tank.
Maybe even float the container so water stays tank temperature.
Then do the treatments for aptasia that you have available. (AptasiaX, Joe's Juice are my two favourites), but I like Joe's juice better.
https://www.amazon.com/s?k=aptasia+joe's+juice&ref=nb_sb_noss
*** DO NOT Cut or burn the Palys's since certain Palys could release very harmful and poisonous toxins ***
*** Wear gloves, and alway rinse your hands **
** Never EVER touch your EYES or MOUTH after touching palys **
Always dump the water in the container to get rid of any Aptasia remenants, and rinse you paly rock before putting back into the container of new tank water.
Wait for a week or so and see if another aptasia shows up. If not put back into you tank and keep an close eye for aptasia to appear. If one does, repeat the above Aptasia out of tank Treatment.
Yes this may be a pain but you will have more work if the aptasia start speading in your tank setup. They will attach and grow , multiply everywhere including glass, pumps, tubing, anything wet with the most minimal of light.
Remember when you distrub, or try and kill the aptasia, it's survival response is to spread if you don't kill it 100%.
