A couple of days ago, one of my lyretail anthias developed a spot of some sort on its tail maybe an 1/8" long. Today the the area of the fin where the spot was is completely gone. The fish is eating and acting fine I just wanted a proper diagnosis and treatment plan. I've tried to search and the best I can tell is that it is bacterial? I've been checking water parameters like crazy every day since, but everything has been good. None of the other fish are exhibiting any symptoms yet.