Pretty cool. My Naso loves Calurpa and I believe that it is easier for them to digest then the Chato. Great fish to have if you can get him on the healthy side!
Are you planing to put him/her in with the other Naso? I ask as I have not heard of that working out so well even if you do find a male and female. That is to say if they are not added at the same time and even then I hear it is pretty risky.
I would be interested in what your plan is to see how it works out.