Right now, I have a pair of Nanochromis teugelsi in a tank beside an immature pair of Pelvicachromis taeniatus Iguedi River. The taenies are happy go lucky, nothing to worry about (yet) kids. They're all over the tank. The teugelsi are wild caught and wary. I just moved their tank last week, and once they'd spotted the taenies through two panes of slightly algaed glass, they got really mad and started angrily strutting. The taenies just kept humming k-pop and being young, and the teugelsi decided they were harmless but annoying enough to be a threat. That's when I saw some early Nanochromis courting moves, and some early nest building. The calm of the juvie F-1 taenies, got them at ease ("if those stupid a%$^$# can stay alive in this place, so can we"?). They didn't even have to be in the same tank.
I find corys, for their reputation as dumb, aren't at all. They are very aware of their surroundings, and will react strongly to the tanks next door or to new fish. I was given a breeder's mistake, some very pretty hybrid killies I won't breed, but will keep for their lifespans, and added them to my panda tank. They worked exactly as dithers would in a Cichlid tank. The Hoplisoma panda are really out and around in numbers. But the no name killies are also far less timid. One looks up, one looks down, and neither sees anyone getting eaten.
