A striking blue-and-black barred dwarf Mbuna from Lake Malawi. Small but famously feisty, it must be kept in a large group to disperse its intense intraspecific aggression.
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Dwarf Mbuna; adults stay around 2.5-3 in (6-8 cm).
Lifespan
6–10 years
Social needs
group
Native region
East Africa (Lake Malawi, Pombo Rocks near Ndumbi)
Origin
Old World
Climate
🌴 Tropical
Water type
💧 Freshwater
Family
Cichlidae
Genus
Pseudotropheus
Part of the African Cichlids
Hardy, vividly colored cichlids from Africa's Rift Lakes (Malawi, Tanganyika, Victoria) and beyond, kept in hard, alkaline, rock-built aquariums. Many are territorial mouthbrooders best housed in robust species-appropriate groups rather than mixed communities.
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Photo coming soon
Minimum
Overstocked mbuna tank
75 gal / 284 L rockscape
Pseudotropheus demasoni is a small (3 in) but extremely aggressive Lake Malawi mbuna. 75-gal minimum, overstocked with 12+ demasoni and added mbuna species to defuse aggression. Massive rockwork pile, hard alkaline water (pH 7.8–8.6).
Photo coming soon
Recommended
Mbuna display group
100 gal / 379 L mbuna display
100-gallon long heavily-overstocked mbuna display with 12–15 demasoni plus other mbuna species, massive rock piles, and strong filtration. Single male demasoni will kill rivals — overstock or single-sex.
Photo coming soon
Ideal
Malawi biotope display
125 gal+ / 473 L+ biotope
Six-foot+ Lake Malawi biotope with massive rockscape, hard alkaline buffered water, and an overstocked mbuna community. Best long-term behavioural balance.
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Photo coming soon
Egg
Fish eggs are small, translucent spheres, often laid in clutches on plants, substrate, or in a nest — or carried/brooded by a parent in livebearing and mouth-brooding species. A dark eye spot and the curled embryo become visible inside as development progresses.
Photo coming soon
Fry
Newly hatched fry are tiny and semi-transparent, frequently still carrying a yolk sac that fuels them before they feed freely. They lack full fin structure and adult coloration, staying near cover until they can swim and forage on their own.
Photo coming soon
Juvenile
Juveniles look like miniature adults but with developing fins and muted or different markings; many species shift pattern and color as they mature. Growth is rapid at this stage given clean water and steady feeding.
Adult
Adults show the species' full size, finnage, and mature coloration, and are sexually mature. Many fish develop sex-specific differences in size, color, or fin shape, which can intensify during breeding.
Habitat & enclosure
Despite its small size, demasoni is aggressive and should be kept in a large colony of 12 or more to spread out aggression, requiring a minimum of about 55 gallons (208 L) with extensive rockwork. Provide hard, alkaline Rift Lake water: temperature 76-82 F (24-28 C), pH around 7.8-8.6, and high hardness.
The tank should be densely structured with stacked rock forming many caves and broken sightlines, which is essential to prevent any single fish being relentlessly targeted. Bright lighting accentuates their electric-blue bars; open sand lanes between rock piles let subordinate fish flee and recover.
Substrate
Use aragonite sand or crushed coral to help buffer the water toward the required high pH and hardness. A sand base also suits their natural sifting and supports stable rock stacking.
Equipment & setup
Oversized filtration is important given the dense stocking needed to manage aggression, alongside a heater and strong turnover. Stack rocks securely on the tank bottom to withstand digging, and add powerheads if extra circulation and oxygenation are needed; CO2 and special lighting are not required.
Diet
A specialized algae-grazer in the wild, so its diet should be predominantly herbivorous. Feed a spirulina- or vegetable-based cichlid pellet/flake as the staple with only occasional small meaty treats like frozen brine shrimp or daphnia. As with other Mbuna, avoid rich high-protein and fatty foods that predispose them to Malawi bloat.
Behavior & temperament
Pugnacious well beyond its size and one of the more challenging Mbuna for this reason; it is not community-safe and is best kept as a large single-species colony or with other robust Mbuna of contrasting color and pattern. Large numbers are the key management tool - too few and the dominant fish kills the rest. Expect constant low-level sparring and territorial chasing, especially among males.
Health
Prone to Malawi bloat from inappropriate protein-rich diets and stress, plus stress-related ich and bacterial infections; chronic aggression itself is a major welfare risk, causing injury and stress-driven disease in bullied individuals. Prevent problems with a herbivorous diet, hard clean alkaline water, very heavy rockwork, and keeping the colony large enough that aggression is diffused.
Tips, DIY & hacks
Stock the colony all at once and keep numbers high (12+) so no individual becomes a constant target. Buffer with crushed-coral substrate to hold the high pH; females mouthbrood the eggs and fry, and removing a holding female to a separate tank improves fry survival.
