Best Friend Tangs - Normal?

My two fish, the Blue Hippo Tang (Paracanthurus hepatus) [2"] and Powder Brown Tang (Acanthurus japonicus) [3"] are best friends. I have a 100 gallon tank, and these two never part ways. The Blue Hippo is always following the Powder Brown wherever it goes! They're like best friends or mates...

Is this normal?!

 

One is afraid that the other is going to get more food! My purple wont leave my Naso alone. He hates him

 

So they're not friends? They don't do anything aggressive, but are always bumping into each other (not with their faces/mouths!).

 

as long as they dont bite each other i wouldnt worry about it. sounds cool though.

 

Ive heard tangs in a tank after they have established territory will usually hang out with each other even if they are different types. My hippo and yellow every so often hang out and chase this large damsel in my tank.