I have a 75 gallon tank with the electric yellows....
and hmm some purple africans about the same size
2yellow
3purps
About a half dozzen rainbows (always have had success with africans and australian rainbows... cant think of any other schooling fish I would want to put with them.
Anyhow.. looking at your tank Id say its a tad over stocked for such aggressive fish.
And though it indeed looks great.. Id say needs more hiding spaces. Perhaps build up even more rock on the back.
Sorry to hear that your having bad luck and hope better will come your way.