Demasoni Cichlid
Pseudotropheus demasoni
Min Tank Size
300L
Adult Size
8 cm
Lifespan
8 years
School Size
12+
About
Endemic to a tiny stretch of rocky shoreline near Pombo Rocks in Lake Malawi, demasoni are one of the most visually striking mbuna you can keep. Those alternating dark and pale blue vertical bars look almost painted on, and a healthy adult in good light genuinely stops people in their tracks.
Don't let the modest 7-8cm adult size fool you though. These fish carry aggression completely out of proportion to their body. Water chemistry needs to reflect their rift lake origins: hard, alkaline, and stable. pH in the 7.8 to 8.6 range with high GH and KH is non-negotiable. Temperature sits comfortably between 24 and 28 degrees Celsius. They're primarily herbivores in the wild, scraping algae off rocks, so a spirulina-heavy diet with minimal protein keeps them healthiest and dramatically reduces bloat risk.
The setup matters enormously. Bare rock stacks with caves and visual breaks are essential. Dense rockwork isn't just decorative, it's functional, letting subdominant fish escape line of sight from dominant males. Sand substrate is appropriate and appreciated.
Keeping them correctly requires commitment to stocking numbers that can feel counterintuitive. A crowded tank with 12 or more individuals genuinely works better than a spacious tank with just a few. Aggression gets divided across the group rather than focused on one or two targets.
This is a species that rewards research before purchase, and browsing real community builds from experienced mbuna keepers will show you exactly how a properly stocked demasoni tank should look and function.
Water Parameters
Temperature
°CpH
GH
dGHKH
dKHSwimming Level
Flow Preference
Keeping multiple Demasoni Cichlid together
Demasoni Cichlid are shoaling fish and need company of their own kind. Keep a group of at least 12. Smaller groups leave them stressed, washed-out in color, and prone to hiding.
Compatibility
Demasoni belong in a species-only tank or in a carefully chosen mbuna community. Compatible tankmates are other mbuna with similar hardiness and aggression levels, species like Pseudotropheus acei, Labidochromis caeruleus, or Cynotilapia afra can work in large enough setups. Avoid any mbuna with similar coloration, demasoni will harass lookalikes relentlessly. Peaceful community fish, tetras, rasboras, corydoras, are completely wrong for this tank. Haplochromines are generally too large or too different in temperament. Cichlids from other lake systems usually have different water requirements and won't survive the aggression either. The tank has to be mbuna-specific.
Commonly kept with
Species this one is most often paired withCommonly tried but avoid
Often paired, but shouldn't beCare Notes
The biggest beginner mistake is understocking. People see aggressive fish and think fewer is kinder. With demasoni, fewer means one or two fish get killed. You need 12 or more, full stop. Second most common failure is diet: feeding them high-protein foods like bloodworms triggers Malawi bloat, which is usually fatal by the time you notice symptoms. Spirulina flakes, nori, and mbuna-specific pellets are the staples. Filtration has to be robust, oversized for the tank volume, because the high stocking density demands it. Stable alkaline water chemistry is mandatory and should be tested regularly.
Behavior & Aggression
Demasoni aggression is relentless and targeted. Males will pursue and kill rival males given the chance, and even females aren't always spared. The trigger is almost always territory and line-of-sight dominance. In underpopulated tanks, a single male can fixate on one target and kill it through exhaustion and injury. Keeping 12 or more individuals splits that aggression across enough fish that no single animal absorbs a fatal amount. Dense rockwork with multiple escape routes helps, but numbers are the real fix. This is not a species you can socialize into being calmer.
Things to Know
- Must be kept in groups of 12 or more to distribute aggression safely.
- Males will kill other males in smaller groups or insufficiently stocked tanks.
- Do not keep with timid or slow-moving species, they will be harassed relentlessly.
- Avoid high-protein foods, they are prone to Malawi bloat from excess protein.
- Overfilter this tank, they produce significant waste for their size.
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