Advise for overstocking rift cichlids

in my opinion, "overstocking" is overused and overrated. Malawi cichlids are best kept in groups of 5 ... one male + four females. in a 55 gallon tank, you can keep two groups of different colors, e.g Labidochromis caeruleus and another group of blue such as Metriaclima or Pseudotropheus. a lot of rockwork with caves equaling one per female plus a few extra. they should be small enough for the female to fit but difficult for a male to access. if you keep Malawi's this way, you don't need 'overstocking' and you'll see "normal" behaviour rather than the more frantic abnormal behaviour of cichlids crowded into a too small space.

can you keep Tanganyikans in there with them? depends on which species you choose but in my opinion, it's not a good idea. neither are Victorian Haps or Aulonocara good tankmates for Malawi's. they're much more sedate and don't appreciate the aggressiveness of Malawi cichlids.

demasoni is one of the more aggressive and territorial of the Malawi's ... again, there are better choices for a 55 gal tank.

for best results, your current cichlids aren't the best choice. i'd rehome most of them and start again with the two groups approach i've recommended.