As per Mike Wise's recommendations from my last thread, I have decided I will try to keep 2 male cacatuoides in my 55 gallon. What are your suggestions for keeping aggression to a minimum? Do males need caves? I previously built some crude caves in my tank using pieces of slate, then covered it with substrate. I read some posts that made me confused on whether or not males use caves. Also, how do these fish fare in a planted tank? I have been keeping plants for most of my time in the hobby, so I am more used to those than any other kind of tank.