Names as polleni - a small spot and bleekeri - big spot - it is not good. True polleni, (year 1868, Bleeker) is not in hobby aquaristic and "bleekeri" (1882, Sauvage) is probably extinct, and not even among breeders. It is better to divide these fish per habitat - small spot "sp. East Coast," a big spot "sp. Andapa" or the incredibly beautiful "sp. Fianarantsoa" see for example here: http://www.malawicichlidhomepage.com/aquainfo/spawning_paratilapia_polleni . Html
or here: http://madagroup.francecichlid.com/articles.php?lng=en&pg=66 - here are some other types of paratilapia too. Official name is only Paratillapia polleni
I have two male and for female "East Coast", this is so nice fish. My friend from "madagroup" (second link) promised some "sp. Fianarantsoa" for me at an early date - I am so enjoying!
When I had them the Polleni didn't get as big as the Bleekeri. The Polleni had the smaller spots. The polleni would spawn but seemed to be egg eaters. The Bleekeri are tough to breed. The Bleekeri seemed to be the more aggresive fish as well.