I looked at Casey's tank and think this is amazing. It along with a few others is what I am trying to achieve in the future. I have always been told to give corals plenty of room from each other as they will sting and kill what is around it if any corals are too close. But in the case of Casey's tank, I see the corals are basically on top of each other which creates a really full tank like I want. So what is true? Do the corals actually sting each othere?