I have a 350 gallon reef tank . In my car and I have 4 purple tangs , 1 chevron tang, 1 yellow tang , 1 large hippo tang ( second in command) and 1 very large sailfin tang( the boss) . Yesterday I acquired a gem tang put him in last night with lights off. This morning only the chevron was showing aggression to the gem. That are the closest in size so I’m thinking they are establishing the pecking order. Hoping all is well when I get home from work.