Tony, we have removed any decent sized copperband that was added to a tank with "any" established tang.
What may work is to find a small one thats eating mysis. Tangs seems to
ignore the small ones. When I pulled my 2 yr. old coperband for nipping
clams, he lived in my sump for a bit. After selling the clams, I put him back
with the Kole he lived with for 2 yrs. The Kole would have none of that. I
had to remove the Kole and let the copperband get established, then
replace the Kole. They were fine.
Mine is now the only large fish in my 65g or 75g, {depending on which week it is,
}. He seems to be fine with the smaller sized tanks, as long
as he,s the boss like AJ mentioned. However he does add a decent load,
from the daily clam feedings & all the frozen foods he requires. For that
reason alone, I may find him a larger home.