I have found that JDs (even in nature) do somewhat poorly when they share waters with other cichlids (especially very dominant territorial ones), and that most central and north American cichlids (JDs come from Mexico, part of north America), have a more more heightened aggressive side in comparison to most South American cichlids from east of the Andes (like oscars).
In the first video below note how torn up the JDs are when in a habitat with other cichlids (Mayaheros uropthalmus)
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But below, in a Cenote where the JD population is high, and they share the waters with mostly non-cichlids (Sail fin mollies and catfish, where other species of cichlids are few and far between), they do much better.
Eden2
So after watching them in nature, my take has been JDs do better in a species only tank, with dither fish, and not a mixed cichlid community.