hola mama.
in a 54 gallon, corner tank(right?) i would stick to some of these set-ups.
1 - african, Mbuna tank, around 5-7 fish.
2 - s./central american dwarf cichlids. 10-20 dwarfs, and only dwarfs! no alrge cichlids.
3 - ANGELS. the 54 corner would make a PERFECT home for these guys. keeping around 5-7 of them.
4 - Discus. same as for the angels, but only 2-3 of them, and these guys are harder to take care of, and require more maintenance.
5 - ONE large cichlid, not over 12 inches adult size. can be either african or s. american, your choice. i would get one of the following: Midas, Red Devil, Red Terror, Green Terror, Jack Dempsy, Frontosa, or Venustus. all of them are good hardy cichlids.
6 - A severum tank, keeping 2-3.
7 - a parrot tank, a pair of parrots. and if they are reproductive, you'll have a blast