Hey folks........
Having kept a 6-7 of these guys, including a few currently I wanted to give some feedback.
First, realize there are 2 varieties of this fish - Paratilapia Bleekeri (large spot) and Paratilapia Polleni (small spot). Temperament-wise, IME, the Bleekeri are considerably more agressive toward tankmates and get larger. Sexing them is difficult. In my experience I saw one male about 9" at a LFS. Otherwise I have never seen a specimen larger than 7".
Tankmate-wise, they mix better with moderately agressive New World cichlids. For ex: I wouldn't put them in with Rift Lake fish.
Both Polleni/Bleekeri are beautiful open-water swimmers from Madagascar that tend to patrol the mid to top regions of tanks. And they need large tanks. My larger specimens were kept in a 125. When happy, these fish are jet black with gorgeous turquoise and white spots. When stressed or unhappy, they turn grayish brown.
Their diet seems to include everything: Pellets, flakes, krill, worms..etc..etc...mine ate everything...HTH....