In my opinion 90 gals are made for Angels or Discus.
So I'd either look at doing a planted Discus tank with 5 or 6 of them. Or look at doing a planted SA community tank with 2 pairs of Bolivian rams, a trio of apistos, and a pair of Peruvian Scalare Angels. Of course with either set up you also have to add tetras, corydoras and otocinclus.