That’s interesting… I’ve had the total opposite experience with scopas tangs! 4’ tank and a scopas never let other fish into the tank. This was a while back (I had to downgrade to a 3’ tank with the same fish… biggest mistake ever). This is an FTS of my 3’ tank and the monster is in the middle just off to the left by a bit, above the Damsel.A tomini tang is a type of ctenochaetus genus. In that size tank it is advised not to have more than one tang from a certain genus. From what I have experienced, scopes tangs are not aggressive in fact one of the most timid and laid back fish I have owned. The yellow tang is most often peaceful as along as it’s with no other zerbrosoma tangs. The purple tangs is the most aggresive zerbrosoma tang.