Like others have said, it's kinda hit or miss with cichlids as they all have different personalities. That said, you have to keep aggressive fish with aggressive fish. If one fish shows weakness it will get nipped to death in no time. You have a better chance of success if you grown everything in the tank from a young age. That said, in a 200 gallon you have a fair chance of keeping some aggressive fish together. Just make sure you put some hiding spots. Also, remember, you can keep big plecos with just about anything.