hey lionfish i was going to get them but i tried peppermint shrimps first. You will need five or more and in 7 days they were gone. Manhattan Aquarium has the for 5 bucks each.
The trick is to cut back on feeding the tank so they will eat the aiptasia. once all gone then feed as usual.
they won't eat other Anemones except for Aptasia. They are great but a littel expensive. awesome Aptasia eaters. if your aptasia is gone and you want to pass on those Berghias let me know i have a 12 gallon that has so much aptasia and i need to clean it up.