Petrochromis trewavasae

Petrochromis trewavasae is a member of the genus Petrochromis, which feeds by combing the algae layer off rock surfaces with the many small teeth in its mouth. Its dark brown-black body is covered with dense, light-colored spots; the upper and lower tips of its tail lengthen with age. It reaches about 15 cm. It is larger, stronger and usually more quarrelsome than Tropheus, and it is intolerant of its own species and of fish with a similar diet. For this reason it is kept only in large aquariums, in a large harem.

• At least 450 liters and 180 cm of length for one male and 4–6 females.
• Plenty of rocks that break lines of sight and wide, well-lit rock surfaces.
• pH 8–9, hard and stable water; a 30% water change every week, high oxygen.
• No plants are kept; they get eaten or uprooted.

Herbivorous. Low-protein food based on spirulina and vegetables is given in small, frequent portions. Carnivorous foods and bloodworms cause bloat.

It defends its territory fiercely; weaker individuals are chased constantly. The female is a mouthbrooder and produces a small number of large fry.

Good companions: in a large tank, Cyprichromis and Synodontis catfish; with enough space, large groups of Tropheus.

Avoid: small and calm Tanganyika species, shell dwellers, long-finned species, shrimp and plants.