I wanted to post an update and good news in case someone else runs into this issue. I was going to give away one of the Firefish but I simply could not catch him. I prepared for the worse but what has happened is that the 2 purple firefish have simply ended up moving to opposite corners and are now both doing well. My clowns seem to go from one to the other to socialize and the 2 purple firefish even mingle now every now and again with no more issues. Whatever territorial dispute happened seems to have worked itself out.