So that's why my brother has a ~55g with JD, 2x GT, 1x RD, 4x Firemouth, 1x Oscar and they are all in perfect condition, and his Oscar won in a local contest.
He's running 2x FX5 and 1 internal UV sterilizer on the tank.
I realise you are only stating a large tank size with all the best of intentions for the fish, but what you are saying now is misleading people, to think bigger is always better.
There is absolutely no aggression in his tank, other from the breeding firemouths, but they don't do any damage.