Fifty-Five Gallons Is the Entry Point
Peacock cichlids, the Aulonocara group from Lake Malawi, are not nano fish with big personalities — adult males reach roughly four to six inches, females stay drabber and slightly smaller, and a group needs a fifty-five-gallon tank as a starting point. Choose seventy-five gallons if you can, especially for an all-male display group, because the extra foot of length is what turns constant skirmishing into separate, defendable territories. A single peacock in a smaller community tank usually fails twice over: the fish is stressed by confinement, and its Malawi water and temperament needs clash with soft-water community species.
Territories Are Measured Along the Rocks
A male peacock's world is a cave mouth or a patch of sand beside rock that he displays over, digging and fanning to attract females. In the wild these territories spread along a rocky shore; in glass, that shore is the aquascape you build. Stack stable rockwork along the back and ends of the tank with several caves and through-routes, leaving open sand in the middle for display and swimming. One cave in a fifty-five-gallon tank creates one winner and several harassed losers, so the rockwork count, not just the water volume, decides whether the group lives peacefully.
Stocking a Group That Can Coexist
Peacocks are the gentler end of the Malawi cichlids, but males of the same or very similar colour forms fight and hybridise, so stock distinct-looking species, keep one male of each form, and either add a proper group of females per male or run a deliberate all-male tank with enough individuals to spread aggression. Overstocking slightly, with strong filtration to match, is a recognised Malawi strategy because no single fish can guard everything — but it raises the water-change commitment, and a lightly stocked, rarely cleaned tank is healthier than a crowded, neglected one.
Water and Feeding for a Malawi Setup
These fish evolved in hard, alkaline, exceptionally clear lake water, so aim for a stable alkaline setup with crushed coral or aragonite-type substrate helping to buffer it, strong filtration, and generous weekly water changes to hold quality in a busy tank. Feed a quality cichlid staple with vegetable content and avoid rich, fatty feeder foods; peacocks are omnivores that pick invertebrates from rock surfaces, and an over-rich diet is a common route to digestive trouble in Malawi fish. Watch new additions for sunken bellies or stringy pale waste and isolate a fish showing them rather than treating the whole rockwork blindly.
Reading Aggression Before It Becomes Damage
Some chasing is normal peacock politics; the red flags are a fish hiding up behind the filter for whole days, torn fins that never heal, or a male who has gone dark and stopped eating. Rearranging rockwork during a water change can reset territories when one male takes over, and a spare tank or divider is worth having before a crisis, not after. Photograph each male as his colours develop so the household can tell individuals apart when describing who is bullying whom. Those shared photos and notes make a real difference here, and KinsLe Family Sharing lets family members share the same tank profile and care details instead of relying on memory.