The tank (as said by others) is too small for dovii alone, and even too small for "more" than just a pair of any Parachromis.
Jack Dempseys usually don't do well with any larger aggressive cichlids, other than them selves, maybe housed with a group of Thorichthys in that size tank would work.
Even in nature when in a habitat with other large cichlids JDs do poorly, even with thousands of gallons of space .
See how torn up they are, and few and far between in the video below.
027 zps4b102ffd
Below however, they are the main cichlid in this larger Cenote (without other cichlid competition) where they do much better, with only live bearers, and catfish.
Eden2
Doing lots of research first helps, but most cichlid community tanks are hit and miss, due to cichlid individual personalities, so it will be only your own experience whether it works or not.
Expect conflict and death, and have hospital tanks available as they grow.
I have found if you keep cichlids together that look alike (same mouth shape, same color, same body shape), their will most likely be problems because they see each other as completition.
If you err on the side of different body shape, mouths, colors, success is more likely because differences mean different needs.
