Hey guys so I am setting up a 75gal for a single fish.I am not sure what I want yet. I just know I want something very aggressive. I have a 120gal waiting to be set up, so if the fish outgrows the 75gal that is ok, I would like to see what the most aggressive fish are that will live in the 75gal for at least a year before out growing it. What would you suggest? thanks!