I recently picked up a never-used 5.5 gallon tank with a heater, HOB Tetra filter (the 10g model) and a canopy with lighting for $6 at a yard sale. Originally I planned to get a couple of cherry shrimp and a small school (6 or so) black neons, rasboras or similar-sized fish. However, when shopping around for potential future occupants at the LFS, I ran across the Nannacara cichlid. Apparently they're pretty peaceful fish and stay really small (smaller than a ram I'm told). Could I keep a single fish in a 5.5g tank, or would it pine away for a breeding partner? If it's even possible to have a pair in a tank of this size, could that be a possibilty?