Although beani like haitiensus are the only endemic cichlid in their natural habitat, which would suggest that they don't play well with others of their ilk, I believe their ideal temp range seems to be much lower than haitiensus. Where as a hait will stress into disease if temps drop into the mid 70s F, beani seem to stress out at higher temps, low 80s. So far I'm keeping the beani in the low 70s, and allowing night temps to drop into the high 60s. Don't know if this is the reason, but I am not seeing any serious aggression yet, even though there are a dozen coexisting in the same tank. I had an adult pair of beani die of columnaris last summer during a heat wave.
I remember Dan Woodland wrote an article a few years back in Cichlid News mag, saying his almost froze with little ill effect, this and the fact that they are the northern most cichlid on the Pacific coast, is leading me to keep the temps cooler, at least for the time being.