Mokele-Mbembe Bichir Care Guide - Aquarium Setup, Diet & Breeding

The Mokele-Mbembe bichir is a fascinating primitive-looking fish with an elongated, cylindrical body and a row of separate dorsal finlets along its back. Its earthy brown to grey colouring, often marked with darker mottling, provides effective camouflage among submerged roots, leaf litter and shaded river margins.

Like other bichirs, it has a long, low-set body, paired pectoral fins and a broad, paddle-like tail. Its armour-like scales and distinctive finlets give it an almost prehistoric appearance, which has made the species popular among aquarists who enjoy unusual freshwater fish.

This is primarily a nocturnal and crepuscular predator. It spends much of its time resting among cover or moving slowly along the bottom, using an excellent sense of smell to locate prey. Although it can appear calm, it is opportunistic and capable of swallowing surprisingly large fish and aquatic animals.

Mokele-Mbembe bichirs are air-breathing specialists as well as gill-breathing fish. Their paired lungs allow them to use atmospheric oxygen, an adaptation suited to warm, slow-moving waters that may become poorly oxygenated. They are also accomplished escape artists and can travel short distances over damp ground when conditions permit.

Polypterus mokelembembe is native to the central Congo Basin in Central Africa, particularly slow-moving tributaries and associated floodplain waters of the Democratic Republic of the Congo. It inhabits warm tropical freshwater environments with dense cover and soft, often darkened substrates.

A single adult should have an aquarium of at least 300 litres, with a footprint of roughly 120 by 45 cm; a larger floor area is preferable for fully grown specimens. Use a secure, completely covered lid because bichirs regularly rise to the surface and can squeeze through surprisingly small openings, while still leaving access to atmospheric air. Provide a soft sand substrate or smooth fine gravel, driftwood, rounded rocks, caves and sturdy plants to create shaded resting places without sharp edges. Gentle to moderate water movement and open swimming space along the bottom are appropriate.

Up to approximately 30 cm (12 inches) in total length. Females are generally larger and heavier-bodied than males; males commonly remain closer to 25 cm (10 inches), although individual size varies.

Mokele-Mbembe bichirs are carnivorous predators and should be offered a varied diet of sinking carnivore pellets, earthworms, prawns, mussel, insect larvae and appropriately sized pieces of fish. Frozen foods are useful, while live foods can stimulate natural hunting behaviour when sourced safely. They generally locate food by smell and may feed more readily during the evening or after the aquarium lights have dimmed.

Suitable tankmates include robust, peaceful fish too large to be swallowed, such as larger barbs, Congo tetras, medium to large rainbowfish, severums and other similarly sized peaceful cichlids. Compatible bichirs may also be kept together when the aquarium is spacious and well structured. Avoid nano fish, small tetras, shrimp, snails and other bite-sized tankmates, as they are likely to become prey. Highly aggressive cichlids, fin-nipping species and very territorial bottom dwellers are also poor choices.

Breeding Mokele-Mbembe bichirs in captivity is uncommon and usually requires a mature pair, excellent conditioning and seasonal changes that mimic the rainy period. The pair may spawn among fine-leaved plants or spawning mops, with the male receiving and fertilising eggs using his expanded anal and caudal fins. Remove the adults after spawning, as the eggs and young may be eaten. The eggs hatch after several days, and the larvae initially remain attached to surfaces before becoming free-swimming and accepting very small meaty foods.

Females are usually larger and more robust, while males are smaller and have a noticeably broader, thicker anal fin. The male's enlarged anal fin is used to receive and fertilise eggs during spawning and is the most reliable visible sex difference.