Tyrannochromis macrostoma

Tyrannochromis macrostoma, the Big-mouth Tyrant, lives up to its name with a jaw gape proportionally among the largest of any Lake Malawi cichlid. This ambush predator lurks near the substrate and uses its massive mouth to engulf prey fish whole. Adult males are strikingly beautiful — deep iridescent blue-green over a spotted pattern — but this beauty belies a powerful predatory nature.

Housing Tyrannochromis macrostoma demands respect for its size and aggression. A 600 L tank is the practical minimum, and tankmates must all be large enough to avoid being swallowed. The species is generally less aggressive toward non-prey-sized fish, allowing it to coexist with other large Haps in a carefully managed community. Water must be pristine and well-oxygenated.

This is a maternal mouthbrooder producing moderate-sized broods. The species is infrequently bred in captivity, partly due to the space requirements. Feeding large meaty foods maintains coloration and health. Suitable only for specialists with large dedicated Malawi predator setups.

Water: pH 7.6–8.8, 24–28°C, GH 10–20, KH 10–18; heavy-duty filtration required; 30% weekly water changes. Tank: 600 L minimum; open sandy floor with minimal decor; must be wide enough for the fish to turn and swim freely. Feeding: Large carnivore pellets, whole silversides, large krill; feed every 1–2 days; avoid live feeder fish. Breeding: Maternal mouthbrooder; difficult to breed in home aquaria; females hold 3–4 weeks; isolate brooding female. Compatibility: Only large Haps of 25 cm+; will consume anything that fits in its enormous mouth.