Wow, went from the first post to the last. Nice to see how he has turned out from badly beaten up to a healthy adult fish. What has his diet been, and how often do you feed per day? What about water changes?
I've been thinking of taking my jack back for a GT since all my jack does is hide. You mentioned your GT is alone in a 75g, how would you say his activity is? Is he as "personable" as the red devil/midas/oscar cichlids?