I have one paratilapia polleni, and two paratilapia bleekeri. The polleni is sexed and is around 3 inches, Ive had him since he was about (or a little under 1 inch) and unsexed, all in a 100g. I had the same problem you have probably been experiencing, THERES NO INFO OUT THERE ON THEM (or at least "almost no info") the link danio gave was the same site I used to understand them a little more, but there are also a few more things I might be able to tell you. They have a reputation, according to some of the local fish store owners Ive talked to, as being less aggressive when compared to African cichlids of a comprable size. However, the two bleekeri (possibly a subspecies to the polleni if not a close cousin, the only difference is the size of their spots and location on madagascar where they are/were endemic) are now unsexed and about an inch smaller than the polleni, and he kicks their asses. One of the bleekeri is constantly being chased around the tank and is fin nipped pretty bad once in a while (fanned all the way to the base of its tail with part of the base bitten) . But both the polleni and the bleekeri start off as a white color, they look a little like a white texas cichlid. Later they turn to a brownish color and begin to develop their distinct spots (if the pollenis which you saw were in bad lighting, they are polychromatic from a light brown to white to blue). The males have high foreheads, and in mating the mating pair suspend an egg sack from a flat surface.
Sorry to be so long winded, and dont worry if you buy a polleni and it starts hiding behind whatever it can (theyll do that).
