Genus Petrochromis dwells in a shallow rocky biotope and it is very numerous in the lake. However, it is not much present in the tanks of breeders, since these fish are rather difficult to breed. Some species grow up to larger size and we cannot neglect the fact of their inner species aggressiveness. I have managed to breed Petrochromis trewavasae successfully having just about 30 fish in a breeding group. The tanks were 180 cm long or even longer, with 700 – 800 litre of water. These algofagous species have got well adapted lips with numerous thin teeth to scratch seaweed from rocks. Even if I have  tried to keep majority of plant  in feeding and  have rich feeding, the number of breedings of caught fish has come down a little step by step. Such a finding made me believe  these fish live from the nature and they gradually lose some of the substances gained when living in the wild. This is obvious when  having a closer look at breedings. This feature is, however, not dominant just with genus Petrochromis, it is also visible with tribus Eretmodini.