My tank has been up for a year and I introduced a purple and yellow tang simultaneously so as to avoid aggression.no problems until yesterday when I noticed the two fighting and the yellow with some cuts along its side.started thinking why this was happening after a year with no problems.figured it out pretty quick.I started dosing nopox about a month ago and my tank is now devoid of algae for these two to graze upon.I always added algae based food a few times a week but evidently now I have to add it more regularly.the tangs are now competing for food which is one of the main reasons for aggression in our limited environment. My tank is 150 gal. I'll be feeding more regularly and hopefully it will settle it. That's what I love about this hobby,learnsomething new all the time
