I have a file fish for aptasia control for over a years, (may be longer than that). He has been eating pellets for a long time after there was no aptasia for him to munch on. Recently I notice that he gains a lot in size and wondering why, then I notice the xenia population is declining, to almost none today in this tank. Then today, I saw him picking on the remaining spots of xenia. Now, he is definitely a hero in my war against Xenia.