angry tang

Well for what it is worth in my experience yellow tangs are much more aggressive and territorial than blue tangs. I have been told that yellow tangs should be kept in groups to keep them from becoming over territorial. I have removed yellow tangs from my tank because of constant bulling.

Their is a chance that the two would get along fine as the general rule with mixing tangs is if they are a different shape they should get along, (ie should tangs really don't like their own species when in a small aquarium environment).

Tangs often become worse with age as well so you might want consider removing him for a smaller one.