Berghia nudi's did a great job in my tank. I was away during the blackout of '03. Almost everythng in my tank died and when I got back, I had a total infestation with aptasias. 1 of these guys cleaned it up in no time, but I have to say, after the aptasias were gone, this thing was a goner not long after that. They also like to catch currents to move around, rather than crawl. I pulled the little guy out of my sump 3 times. They may also eat carpet leathers. Nudi's are very delicate, so when you put it in your tank, acclimate it very slow... drip would be best and don't put it in the tank next to an aptasia. An aptasia will eat a newly introduced berghia. I tried joes juice, aptasia stop, injecting boiling water... just about everything with little to no success. Berghia's can do the job, but I don't think it's worth killing one for 5 or 6 aptasias when they could be controlled with good husbandry.