This one just says "Large Groups"
http://www.marinedepotlive.com/754514.html
isnt that sooo helpful
This one claims it doesn't get along with any other Tangs:
http://www.marinedepotlive.com/754514.html
hehe
The book "Your First Marine Aquarium" ISBN 0764104470 states:
"...tangs should either be kept as solitary specimens, or in groups of
at least three."
thanks
--
richard reynolds