Are tangs social or solo?

[SueAubu]

I've looked through the threads and seen all the questions about which tangs are more or less aggressive and what size tanks they need. I'm still left looking for hints aside from the mirror suggestions I'll be using as soon as I hit "post", here. I'm still wondering:
Are tangs preferably social or solo? More specifically, hippo tangs.

I'm combining rescued tanks into a 220g (and ultimately a 500g). I have 2 hippos in two tanks and one is with a yellow tang. How can I expect the hippos get along? They're both around the 4"-5" size. Would they prefer to be solo or are they happy enough with another of their kind in the tank (like Pixar says.. hahahaha)?

 

[Timfish]

Generally, in aquaria tangs will be territorial so when adding them together an aquarist should always be ready to rehome someone if needed. Individual personality is probably the most important variable.