you can keep lot in a 75-90 4 feet is not bad i like uaru and geos or what about spiny eels or bgk.
the most likely of scenarios lolGoldfish.
Hey, if it's 5ft high, 4ft cylinder, you could keep just about anything
1 Leopard puffer (Tetraodon Schoutedeni)
3 cb Senegal birchir with a dwarf macrostoma giraffe cat.
That would make a great little tank.
I was gonna suggest polys too...never go wrong with them lol. But op doesnt want to worry about securing lids.Polypterus are a lot of fun to keep, I'd highly recommend them! Is your heart set on cichlids?