ok, let me try to sum up all of your questions. Labs do come in Blue. They also come in white. This is not a subspecies, but a variation. It is not uncommon for purebred species of yellow lab to brood blue or white variations. It is however, very uncommon to find purebred species. As previously stated, your likely culprit is the Pseudotropheus socolofi. one common characteristic difference to the Pseudotropheus socolofi is the presence of black on the tail. Your tankis not overstocked, Malawi Cichlids should be kept slightly overstocked to control aggression. The Parrot is not an African/Malawi, and should not be kept with them as they require different water parameters. As for the other fish, aggresion will become an issue with the Auratus as they become very aggressive and downright nasty as they reach maturity. The Socolofi will establish themselves a territory and will not tolerate any other fishes entering their cave. The may also show added aggression toward similarly colored species. Hope that was a help.