You should try get 1 male to 3 females ratio or more if possible. Tank size at least 1.5m long & 0.6m width. Plenty of rocks. I suggest that you stock a group of Tropheus with them. Good combination - same diet, don't interfere with each group reproduction. In my experience relatively calmer then other Petrochromis species & easier to breed(but still not so easy :wink
Attached is a video of Trewavasae spawn I captured few years ago:
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