I agree with fishymel. There are many factors to consider when cosidering the overall aggression of certain fish. How many times they are fed, amount of coral/live rock- hiding places, other tank mates, their sizes and their degree of aggression. In some 25 years in the saltwater hobby I have never had a fish just "snap." I 'm sure it does happen but feel it is more the exception and not the rule. In addition, while I am always in favor of big tanks, currently looking at a 680 gallon- 10 feet long- when I lived in Hawaii, and dove everyday, it amazed how most triggers I observed stayed in a relatively small area. Even the massive Titan I would visit everyday- probably 15-16 inches long and 8 inches wide, he was like a bowling ball with huge teeth- hung out in an area that was maybe 6x6x6- unless he was charging us! He/she was protecting a nest some of the time but I observed him/her almost everyday over a 2 year period. Those in this hobby need to read as much as possible and share info with others in the hobby, join a local club. Even after all of that, sadly sometimes, we learn by trial and error and realize that something we did or did not do led to the death of a beautiful animal.