Right now this is just a hypothetical. If my wife thought I was getting rid of 'her' pink convicts I would be in the doghouse.

I'm wondering if I emptied some/all of the current stock in my 55 gallon, what could I put instead?
Thanks for any suggestions.
I'm leaning toward a single or pair of interesting/unique/colorful fish in the tank instead. Possibly up to a small group, but no swarms of fish e.g. not 20 tetras.
Goals:1) Can live in a 55g
- for its whole life or at least several years
- and without the tank looking empty all the time
- so somewhat interactive
2) Doesn't need extreme water care
- e.g. no discus
3) Is not poisonous to my kids
- e.g. no lionfish/toadfish/asian stinging catfish, that sort of thing
OptionsSo, there's a couple ways I could see this going.
1) Oddballs/Catfish
2) Cichlid Solo/Pair
3) Native tank
4)

something I haven't thought of.
Not PossibilitiesHere's a list of what I've kept already or don't plan to consider for this project
CA cichlidsJack Dempseys
Thorichthys species
Cryptoheros species (except possibly Sajica)
SA cichlidsAngelfish
Rams
Apistos
Catfish
Electric catfish
Upside down catfish
Hoplo catfish
Sun catfish
Tankbuster cats e.g. Asian or SA red tail catfish
Striped/spotted/marbled Raphael catfish
Plecos
WA cichlidsWest African tilapia (specifically snyderae, but probably not any of the others either)
Tang/Malawian cichlidsNone of these right now
Oddballs
African leaf fish
African Butterfly fish
Bichir
Green spot puffer
Figure 8 puffer
Dragon Goby
PossibilitiesHere's a list I'm considering. Tell me why any of these are a good choice or a bad one.
CA cichlidsGreen Terror - solo vs. pair?
Salvini - pair in a 55g for a while?
Sajica - too small for a 55/would seem empty?
Catfish
Giant SA Bumblebee Cat - available locally?
Senegal Giraffe Cat - available in the hobby? PC says this one stays under 10"
Ompok Catfish - saw a little one in Indiana
Gulper Catfish - expensive but really cool
Oddballs
Datnoid
- any of these stay small enough for a 55g?
- any that could stay with my Senegal bichir/African leaf fish/African brown knife?
Needlefish (same as needlenose gar?) - probably needs a group and kind of goes against the 'won't hurt my kids' goal?
Archer fish
Anableps/four eyes fish
Native Fish
Missouri Longear Sunfish
Southern Redbelly Dace
Madtom Catfish