Aggressive Cichlid

Question
I'm jst setting up a new 55 gal aquarium with 8 cichlids, one of which happens to be bullying the other 7. I put them in at relatively the same time (a day apart) with a rock fixture in the middle for protection. I've read up on this site and others and have placed a clear plastic tupperware container with a hole in the side on the bottom to offer extra protection. Still no change. All the other fish get along but this one will chase all the other fish up and down the tank. Any help? I want to set up the best environment possible. Do I need to find a new fish or will another take his place as class bully?

Answer
This is common with Cichlids and normally will calm down after a few days to a few weeks, you might want to add some additional decorations to the tank to help break up Territories and to provide addition hiding places for the other Cichlids, This should get things to calm down however there will always be some chasing that happens in a Cichlid tank so as long as your not seeing torn fins or other damage its pretty normal.