I have seen multiple tangs together of variouse species getting along together, But I think it helps if there are more than two tangs in the community, as these fish can be aggressive @ the same time the yellow and blue tangs being the only two tangs in the tank so to speak might just be best freinds, but one will always be more territorial as they will have to compete with eachother for food, space, ect.
SO YES, BUT MAKE SURE THERE ARE LOTS OF HIDING SPACES!
The hepatus tang is a zooplankton eater and generally gets along well with the herbivore families of tangs such as the Zebrasoma and Acanthurus. I would recommend it (heptus) be added first as they are generally more docile.
How would the Whitecheek Tang (Acanthurus nigricans) get along with a Blue Tang (Paracanthurus hepatus) and a Yellow Tang (Zebrasoma flavescens)? Any additional info about the Whitecheek that may be interesting?