I am not so sure. My Tang is housed with a very large Clarkii clown and I put garlic soaked seaweed in the tank and both him and the clown rip it to pieces eating it and I had a Niger Trigger that LOVED seaweed. When I put mysis, squid, pellets and other meaty foods in the tank for the Clarkii Clown the tang is all over that also.
He eats anything I put in the tank, meat or vegetable.