75 gallon cichlid tank?

I've kept aquariums for about nine years, but the only experience with large cichlids I have is a year with a large oscar in my 75 gallon. I had to sell him when I moved. Now I'm about to get my own apartment and want to set it back up. I want another oscar for sure, but I was wondering if I could put an electric blue jack dempsey in with it. I would introduce them young, small, and at the same time. There would be wood and rocks as hiding places. Is my tank too small for this to be a successful mix in the long term?