Blue Petrotilapia, Lavender (Petrotilapia tridentiger) - Cichlid Fish for Sale UK

Shimmering blue-lavender colour and real presence make the Blue Petrotilapia, Lavender (Petrotilapia tridentiger) one of the more imposing mbuna a Lake Malawi keeper can take on. This is a substantial cichlid, reaching around 17cm, and it carries itself accordingly in a large rocky aquarium.

It is a difficult-level fish, not because it is delicate but because of the scale of its needs. A grazing herbivore by nature, it requires a strictly plant- and algae-based diet and a roomy tank with hard, alkaline water. Feeding it the wrong, protein-heavy foods is a common and avoidable mistake with this group.

Occupying the middle of the water column above the rockwork, it is semi-aggressive and can become territorial, so its companions need to be chosen with that in mind. Given space and the right diet, it is a striking centrepiece for a dedicated Malawi system.

Care summary

• Large adult size around 17cm; lifespan up to 8 years
• Temperature 24-28°C, pH 7.8-8.6, hardness 10-20 dGH
• Minimum 300-litre aquarium with extensive rockwork
• Herbivore - feed a plant- and algae-based diet
• Difficult care; semi-aggressive mbuna for a Malawi-only tank

Provisioning for a mbuna of this size is a real undertaking. The 300-litre minimum should be packed with rockwork to break up lines of sight and give it the territorial structure it expects, with the water held between 24 and 28°C, a pH of 7.8 to 8.6 and hardness from 10 to 20 dGH. Mature filtration and disciplined maintenance keep a tank of this stocking level healthy.

Diet is the single most important husbandry point: as a herbivore it must be fed a plant- and algae-based menu, and avoiding rich, protein-heavy foods is essential to its long-term health. Get the space, the water and the diet right and it can live around eight years as the commanding centrepiece of a Malawi display.

Stocking note

Pair it with other robust Lake Malawi cichlids of similar size and temperament, plus large, non-aggressive Malawi catfish or bottom dwellers. Avoid small community fish, slow-moving or long-finned fish, highly aggressive species that will dominate the tank, soft-water fish and delicate invertebrates. Every fish ships with a licensed live-animal courier and the reassurance of our live arrival guarantee.