My yellow tang is agressive and extremely territorial. I know I have too many tangs in the tank, but the relationships/personalities are like this: The naso tang basically minds his own business, just constantly grazing. He is like the unofficial king of the tank and only gets mildly aggressive when hungry. A couple of times he's chased my lawnmower (the offiicial king) who got a little bit too close while feeding.
The yellow and powder brown are always following him around (I think because they believe he knows where the food is, or maybe trying to intimidate him). In the very beginning when I introduced the yellow and the naso together the yellow tried to dominate the naso which would have none of it. The powder brown is not aggressive towards the naso either but both it and the yellow take turns going after the powder blue (which is a little smaller than the yellow). At times the yellow and powder brown take aggressive postures against each other and "tail" fight but not very agressively, just when they go into each other's territory, or when hungry. I feed once daily. Except for the naso, they eat anything I throw into the tank. The naso will eat algae, flakes and he may nip at pellets. He doesn't touch the meaty stuff, at least I haven't noticed.
My favorite is the naso, even though I had originally wanted a blonde naso. I'm thinking of getting additional fish, so I have to decide which of the tangs to get rid of. One thing I'm considering is that it is possible for the naso to outgrow my tank and I don't want to get too attached only to one day have to get rid of it. So...