I would like to bring another point of view into this thread. One that I have thought about over the years and one that now, like Brad, effects myself and my tangs.
I,m also down sizing to a standard 4ft. 75g tank. I was planning on keeping my 5 pyjama cardinals, mandarin and 3 percs only. I have a young juvie yellow tang and my 2yr. old Kole, both of which I was going to find homes for.
Over the last 15yrs. or so, I have sold or traded away several very healthy tangs and a few other fish, because of moving, tank changes or what I thought may be better for them.
However many times they met their demise for what ever reasons. Thus did I do what was best for them? I have always given my fish extremely good care, perhaps to the extent of spoiling them. But thats how I care for my pets, all of them. So would a tang living in a smaller tank or in my case and Brads, two smaller tangs living in a 75, {with good care}, be worse of that being given away. Esp. when I have always believed in providing much more room for them and "preached" such.
For myself, if I was to keep them, I would have to give away my cardinals, which I was planning on trying to raise some young, as the 5 of them just adds to much bio-load with larger bodied fish like tangs.
Anywho, as I sit here and ponder this, I figured it would add another point into the never ending tank/tang size discussions.