+1 on what Dan said. I've seen videos in the wild of them head-bobbing over rocks which mimics the mbuna they are stalking. Pretty neat.
IME, you should never keep S. fryeri with peacocks if you are trying to breed. Pound-for-pound, they are more aggressive than most peacock species, will become dominant and will interbreed with the Aulonocara females freely. (Some peacock females also appear similar to their females)