Tyrannochromis macrostoma

Big-Mouth Hap

Classification

Cichlidae

Distribution

Endemic to Lake Malawi.

Habitat

It inhabits shallow waters in rocky areas.

Maximum Standard Length

14″ (35cm).

Aquarium SizeTop ↑

72″ x 18″ x 24″ (180cm x 45cm x 60cm) – 485 litres.

Maintenance

The tank can be quite sparsely decorated but provide some large rocks to act as cover. A substrate of sand is the best option. Obviously, powerful filtration is required in order to deal with the large amounts of waste produced by this predatory fish.

Water Conditions

Temperature: 75-82°F (24-28°C)

pH: 7.6-8.8

Hardness: 10-25°H

Diet

Will accept dried foods such as pellets but these should not form the basis of the diet. Although this fish is a piscivore by nature, it can easily be trained to accept dead foods in aquaria. Prawns, mussel, cockle, lancefish etc. are all ideal.

Behaviour and CompatibilityTop ↑

A predatory species with a large mouth that should not be kept with fish under around 5″ in length as they will be eaten. This is particularly true for mbuna, the natural diet of this fish. It is peaceful with species too large to eat, and can be combined with other large haps, but do not keep it with species requiring a vegetarian diet.

The male fish become territorial during spawning. Several females should be kept per male, and only one male kept, unless the tank is enormous.

Sexual Dimorphism

Adult males are more colourful than females.

Reproduction

Not known to have spawned in aquaria. Maternal mouthbrooder. In nature males excavate large, crater-like pits in the substrate and defend these against other males. Spawning occurs in these pits. Brood care by the female is known to last for some time in this species.

NotesTop ↑

T. macrostoma is an ambush predator in nature, lurking behind rocks and in crevices as it stalks its prey. It is rarely seen in the hobby and is usually quite expensive. Juveniles are easily confused with the similar T. nigriventer, but are easily distinguished when adult, as nigriventer does not develop the dark belly of macrostoma.

Interestingly, this species exhibits reverse countershading, as also seen in the common Upside-down catfish, Synodontis nigriventris. This means that unlike the majority of fish species, it’s belly is darker than it’s back. In T. macrostoma, this is thought to derive from the fishes’ hunting technique, as it often attacks prey whilst swimming upside-down, the reverse countershading making the fish harder to spot.