For my money, angels complement geos nicely (I prefer wild angelfish) as do a number of other fish, including severums, some acara, etc. With a disc shaped fish like angelfish, you get a contrast in shape, movement, and body language, to your geos. (It kills me when people say the difference in body language is between Africans and new worlds, to the point fish from the two continents can't understand each other. That's not it at all if you observe them long enough. More peaceful, yes, but my OH tapajos are actually similar to peacocks in body language, resembling their behavior much more than they do discus, severums or angelfish.)I am currently thinning out my 100g south american stock and once complete will leave me with x3 sp.leucosticta, x4 juvi orangeheads and a larger male, a juvi green phantom plec, and a small shoal of lemon tetra.
Other than the tetra all the others are generally speaking bottom dwellers and I want something south american to fill out the upper part of the tank - are angel fish a good option?
Are angels strictly top dwellers? Not ime, but geos are not strictly bottom dwellers either ime. But, similar to geos spending a lot their time oriented to mid water and bottom, angels spend a lot of their time oriented to mid water and top, if that makes sense. While geos will spend time sifting sand for food, angels will be looking for something at the surface. But with either type it's not like there's an invisible boundary they never cross.