CA cichlids temps

If you research temps of rivers in Central America, such as the Grijalva-Usumacinta, you may be surprised to find temps as low as 22'C (72'F) in Feb, and rainy season, up to as high as 30'C (86'F) in Sept.
But because I find pathogenic bacterial populations to be most virulent in higher temps (82'F and above), I try to keep temps in the low, to mid 70s'F in my tanks.
And because I keep some of the more northern species such as carpintus, or beani, and some of the southern South American species, (Gymnogeophagus) lower temps for their tanks may be best, so I keep them unheated, on north walls.
Here is a Australoheros sp "red ceibal" grow out tank thermometer.

and below, an average winter temp in my tanks (this pic was in a beani tank at time of their spawning).

Researching the rivers our fish come from also gives clues to average pH and other water parameters,
Lake Lachua where argentea, heterospilus, pearsei and lentiginosus come from varies from 8 - 8.5pH.
And although I keep many of those species, and my pH averages 7.5, consistency with water changes to keep pathogens down is more important to me, rather than trying to exactly mimic the research.
below Theraps lentiginosus

I also prefer lower temps, because the lower the temp, the higher the ability of water to hold oxygen.
In my area, natural fish kills are most common in summer when oxygen saturation is lowest, temps are highest, and pathogenic bacterial populations are at their peak.
I have only kept 2 species that require really high temps, Nandopsis haitiensus and Acalapia alcalicus.
And it seems these 2 species have evolved an immune system that is able to fight off these higher temp bacteria, whereas many other cichlids have evolved for other type.