I HAVE AN UNDULATED THAT IVE KEPT FOR A FEW YEARS NOW IN WITH 13 OTHER TRIGGERS IN A 500 GA, AND TANGS AND WRASSES AND A FEW OTHERS. THE UNDULATED SO FAR KEEPS TO ITS OWN AREA, ONCE IN AWHILE IT SQUABBLES WITH MY WHITE LINE TRIGGER,NOTHING SERIOUS.I KEEP THEM WELL FED. IVE NOTICED AS LONG AS THEY HAVE THEIR OWN SPACE THEY ARE OKAY.