@Wills has suggested great African fish for hard water, and
@Back in the fold has North/Central Americans with the same need for minerals. If you have Apistos, you probably have soft water.
All dwarf Cichlids will be shy. Something that size that ran around saying 'look at me' in their habitat would be on someone's menu in minutes.
The best, in my opinion?
Western African Pelvicachromis kribensis. They aren't kribs (P pulcher) but a smaller, more colourful fish. There was a misidentification 80 years ago.
Apistogramma veijita, hongsloi or macmasteri;
A cacatuoides;
Nannacara anomala;
Nanochromis - any of them;
Dicrossus filamentosus - the lyretail checkerboard Cichlid ( a fantastic little cichlid from SA that will show in groups of 6, and is inexpensive when you can find it).