will these be the only tangs? If you have any others I already in there I suspect you will have your hands full. two tangs that are identical almost always will fight. You may get lucky though. Even tangs that are slightly similar fight, like if they have the same color or the same shape. I've gotten somewhat lucky in that my tangs dont fight. I have a hippo, yellow, tomini and one that looks like a mustard tang. The mustard one and the tomini are very similar in shape and coloring too. I consider that luck that they get along. I do have a 6 foot tank and provided LOTS and LOTS of hidey holes for each fish to call their own. That would be my best recommendation, make sure they have plenty of places to run to in order to escape aggression. And as was stated above, the long term issue still has to be ironed out as they will get huge, too huge for your tank. I;ve seen small tangs fight and it's horrible, but big ones? That could be a literal bloodbath.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.