Congo Bichir Care Guide - Aquarium Setup, Diet & Breeding

The Congo Bichir is a large, ancient-looking freshwater predator with a long, cylindrical body, a flattened head and a row of separate, sail-like dorsal finlets. Its sturdy pectoral fins and earthy brown, olive and grey colouring give it an unmistakably prehistoric appearance, while the small eyes reflect its largely nocturnal habits.

Polypterus congicus is one of the largest bichirs available to aquarists. It spends much of the day resting among cover and becomes more active after dark, using its excellent sense of smell to locate prey. Although it can swim normally, it also moves confidently along the bottom with its muscular fins.

Like other bichirs, it retains primitive lungs and can breathe atmospheric air. This adaptation allows it to survive in warm, poorly oxygenated waters and is reflected in its habit of regularly visiting the surface. It is also an accomplished escape artist when given the opportunity.

In the wild, Congo Bichirs occupy habitats that range from open river channels to quiet, vegetation-filled floodplain pools. Their lineage is extremely old, and their armoured scales, paired lungs and distinctive fin structure preserve several features associated with early ray-finned fishes.

The Congo Bichir is native to the central African Congo River Basin, including parts of the Democratic Republic of the Congo and the Republic of the Congo. It inhabits slow-moving rivers, floodplain waters, swamps and backwaters with dense cover and soft bottoms.

An adult Congo Bichir needs a very large aquarium of at least 1,000 litres, with a footprint of roughly 240 × 90 cm or larger; bigger specimens and groups require substantially more room. Use a secure, completely sealed lid because bichirs regularly surface for air and can force their way through surprisingly small gaps. Provide a broad floor area, gentle circulation, shaded retreats, sturdy driftwood, smooth rocks and caves, with soft sand or another smooth substrate that will not damage the fish as it rests and forages. Leave clear access to the surface and avoid unstable decorations that could be shifted by this powerful species.

Up to about 97 cm (38.2 in) in the wild; aquarium specimens are often smaller, commonly around 60–75 cm (24–30 in). Females generally grow larger and heavier-bodied than males.

This carnivorous predator should be offered a varied diet based on meaty foods. Suitable choices include earthworms, prawns, mussels, chopped fish, insect larvae and high-quality sinking carnivore pellets. Frozen foods are useful staples, while live feeder fish should be avoided or used only with great care because of disease and nutritional risks. Young fish usually need more frequent meals than adults, and uneaten food should be removed promptly.

Congo Bichirs suit large, robust community aquariums containing peaceful or moderately assertive fish that are too large to be swallowed. Suitable companions can include large Congo Tetras, mature Synodontis catfish, large peaceful cichlids, datnoids and other substantial African or South American fishes with compatible water requirements. Avoid small fish, shrimp and ornamental snails, which may be treated as food, as well as fin-nipping species and highly aggressive cichlids. Other bichirs can sometimes be kept together, but the aquarium must be exceptionally spacious and provide plentiful cover.

Breeding Congo Bichirs is uncommon in home aquariums because mature adults require exceptional space and carefully managed seasonal conditions. A large, mature pair may spawn after heavy feeding and changes in temperature and water movement. The female scatters adhesive eggs among fine-leaved plants or a spawning mop, while the male receives and fertilises them with his enlarged anal and caudal fins. Eggs and fry must be separated from the adults, and the tiny larvae need suitably sized live foods as they develop.

Females are usually larger and more robust than males. Mature males have a noticeably broader, thicker anal fin, which they use during spawning to receive and fertilise the eggs; females have a narrower anal fin.