
Some of the key words in the original post of importance here, may be, "a few ".
In nature danios, and other dither species, is that, as a few, the danios may not be comfortable themselves, so can be produce a counter dither effect.
If you look at the shot above, from a Cenote in Mexico, the dithers are many, that gives "them" a sense of security, and at the same time, the cichlids watching them, instinctually sense their security , so feel secure themselve (dithers are cichlid early warning systems).
Once the danios settle in, this may change, unless the cichlid is sniping at them.
in the video below from another Cenote, compare numbers of dithers to cichlids.
Eden2YouTube · Duane Stuermer4 minutes, 41 secondsJan 16, 2014