I need some expert opinions..IDK if this is some type of bacterial infection, and also if It can be cured.This Tank is about four years old. I’ve been successfully keeping acros with no issues until now. Approximately one year ago I placed a few new acro frags into the tank. Three months back I started to noticed this issue and I removed the affected Acro. Now I’ve noticed it on several others. What should I do now? Can’t really find much on this issue besides a possible bacterial infection.