I haven't had to deal with aggression in my mostly thorichthys and cribroheros 150g. Sure there are little thorichthys squabbles amongst the same species (meeki, mixteco or pasionis), but they don't harm each other. It's pretty funny to watch at times actually. Each fish really has a lot of personality. The cribroheros will ignore everything and just go about their business in sand sifting. These cichlids in a big enough tank will work out in the long term. If you are looking for a peaceful CA set up, I highly recommend these guys.