I forgot to mention a good alternative to Pbass are Petenia splendida. They are the hard water equivalent of peacock bass.
I agree with this, and about what Rocksor said about "in house water softening". (if you come from a hard water area, Petania would be a much better choice of species)
What you should probably do, is find out about the parameters of your tap water (from the garden hose, and the softened tap), and plan your stock accordingly.
Your city water EPA water Quality Report would have that info, maybe even your water bill.
Cichla are generally soft water species (real soft, not chemically softened) and in hard water "can" become subject to HLLE scarring and other bacterial infections, although not quite as bad as oscars, chocolate etc..
Unless.......you got the P-bass that have been breeding in the hard waters of Florida for the last half century.
There are also P-bass that have been breeding in the hard semi-salty waters of Lake Gatun in Panama, so have over time evolved to live in less than optimum conditions for the species. (of course the don't grow as large here in Panama as they do in the soft waters of Amazonia).
It would be interesting to know how many young died due to less than the right water, compared to how many were able to adjust thru survival of the fittest.
There are enough P-bass now in the lake, there is a yearly fishing jamboree just for them.
