Can I put tangs or triggers in a 4' 120gal tank? I keep reading you should have a 6' 125gal tank, but I was wondering if I could create a rock mountain in the middle of the tank so there would be room to swim all the way around the outsides of the tank. I don't want to put anything in an enviroment that would cause any undue stress. I haven't bought the bigger tank yet, just wanting to know if its a possibility. I do not have any plans for a reef tank at this time and I'm not sure a 6' tank would fit in my place.