But it was always a bit of a disappointment to me that, once settled in and comfortable, they didn't really "school" anymore. Even in an 8-foot tank they start to get pretty cocky and just go their own ways; you have a scattering of tetras throughout the tank, each doing his or her own thing, swimming every which way and not really paying much attention to each other. To me, a lot of their charm is when they are schooling, but unless you keep them off-balance and terrified all the time...not recommended!

...that behaviour pretty much vanishes.
Have you considered livebearers? Swordtails and cichlids look great together. I don't know anything about O.heterospia; is it a harder-water higher-pH cichlid? If so, swordtails, mollies or Goodeids like Xenotoca or Ameca would be a perfect fit, better than tetras from soft acid water.