Because birds are some of cichlids main enemies in nature, so many of the colors that are bright in aquariums as seen from the side, help to camouflage in nature, and make cichlids invisible to predators from above.
The metallic scales of turquoise, gold, and red often blend in with the light on shimmering water, and with suns reflection.
Here are some examples, imagine on a dark substrate how easily these might disappear.
Far right in the pool/pond pic are Australoheros red ceibal
in the middle Gymnogeophagus
and far left xCichlasoma beani
My point is, the cichlids from deep waters, that are "not" often bird prey, would a good choices.
Midas are often found in deep water, but might be a poor choice as far as aggression goes.
Lemon yellows (Labidochromis caeruleous) might also be more apparent in a pond environment.
I keep cichlids in my ponds, mostly for breeding purposes, but most of the time, they are invisible.
The pond below had hundreds of cichlids last summer.
