I was a FOWLR guy for years, nah never had ANY aptasia. This time around, it took 4+ years, and 3 tanks later finally saw one over the weekend. I smothered it with kalkwasser paste and glued over it. Lol. I almost removed the rock and promptly burned it with fire, but I like the zoa garden that's finally growing off the plug.Lol. Anyone that votes no either hasn't been in the hobby long enough or hasn't looked close enough. The right tank inhabitants will hide the problem until you look in overflows, plumbing, or sumps.