It works for me. Jaguars included. The fewer cichlids I have in a tank, the more aggression....my overcrowded growout is WAY overstocked and there is no aggression, jut one Devil that occasionally throws her size around and flaunts who's the biggest from time to time. That keeps everyone in check.I have had this work with Africans, and even certain new world species.
The theory is with so many heads bumping together, there is no chance any one can take over. It has worked with more shoaling social species like Astatheror and Geophagines, and some Madagascans, but only in large enough tanks, and not with Parachromis or more aggressive loner types.
But also only works if water quality is maintained, which can be difficult unless water changes are stepped up beyond the norm. With my overstocked tanks I found I needed daily, or at minimum every other day water changes.
This can only be done when the amount of caves is 2-3x more than the amount of fish. Don't waste your time trying it in open or planted. You need rockscape for it to work
Weekly 70% WC are all I need for good water