Banded Bichir

Quick summary

The Banded Bichir is a hardy, long-lived predator best suited to intermediate to advanced fishkeepers who can provide a large, securely lidded tank of at least 300 litres and appropriately sized tank mates. It’s not ideal for beginners or community tanks with small fish, since it will eat anything that fits in its mouth and needs specific setup considerations to thrive.

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In this guide:

• Introduction
• Quick Stats
• Appearance
• Natural Habitat
• Tank Size and Setup
• Water Parameters
• Filtration and Equipment
• Diet and Feeding
• Behaviour and Temperament
• Tank Mates
• Breeding
• Common Diseases
• FAQs

Introduction

The Banded Bichir (Polypterus delhezi) is one of the most visually striking members of the ancient family Polypteridae, a group of primitive ray-finned fishes that have remained largely unchanged for hundreds of millions of years. Native to the rivers and floodplains of the Congo Basin in Central Africa, this species captivates fishkeepers with its bold dark banding across a pale olive or greyish body, its unmistakable elongated form, and its possession of functional lungs that allow it to breathe atmospheric air. For aquarists seeking a truly prehistoric-looking centrepiece fish, the Banded Bichir delivers in spades.

Polypterus delhezi is sometimes referred to as the Barred Bichir or Armoured Bichir, though “Banded Bichir” remains its most widely used common name in the aquarium trade. It belongs to a genus of roughly a dozen recognised species, all of which share a distinctive appearance characterised by a series of dorsal finlets rather than a single continuous dorsal fin, thick ganoid scales that provide armour-like protection, and lobed pectoral fins reminiscent of those seen in early tetrapods. This species is moderately sized for a bichir, typically reaching around 35 cm in captivity, making it one of the more manageable members of the genus for home aquaria.

While the Banded Bichir is a hardy and relatively undemanding fish once established, it is not a species for absolute beginners. Its predatory nature, specific tank requirements, and need for a secure lid all mean that a degree of experience and planning is advisable. That said, for intermediate to advanced fishkeepers willing to provide an appropriately sized and furnished aquarium, P. delhezi is a rewarding and long-lived companion that can survive for well over a decade in captivity. This guide covers everything you need to know about keeping, feeding, and breeding the Banded Bichir in a home aquarium setting.

Appearance

The Banded Bichir possesses the classic elongated, almost serpentine body shape characteristic of all polypterids. Its body is cylindrical and slightly compressed laterally, tapering towards a rounded caudal fin. The base colouration is typically a pale olive-green, greyish-green, or yellowish-grey, overlaid with a series of bold, dark vertical to slightly diagonal bands that run along the length of the body. These bands are usually dark brown to black and vary in width, spacing, and intensity between individuals, giving each specimen a somewhat unique pattern. In some individuals, the bands may break up into irregular blotches or spots, particularly towards the tail.

One of the most distinctive features of the Banded Bichir – and indeed all polypterids – is the dorsal fin, which is divided into a series of separate finlets, each supported by a single spine with attached soft rays. In P. delhezi, there are typically between 9 and 13 of these finlets running along the back. When the fish is alarmed or displaying, these finlets can be raised individually or simultaneously, creating a remarkable saw-toothed silhouette along the dorsal surface.

The pectoral fins are fleshy and lobed, attached to the body by a muscular stalk that allows the fish to “walk” along the substrate and prop itself up on the bottom – a behaviour that immediately brings to mind the fish’s ancient lineage. The pelvic fins are positioned well back on the body, and the anal fin is small and set far posteriorly. The skin is covered in thick, diamond-shaped ganoid scales that have a hard, enamel-like coating, providing substantial protection from abrasion and even from bites by other fish.

The head is broad and flattened dorsoventrally, with a wide mouth and nostrils that are carried on short, tubular protrusions. The eyes are relatively small and somewhat poor in visual acuity, as bichirs rely far more on their keen sense of smell to locate prey. Juvenile specimens tend to display external gills – feathery, larval gill structures protruding from behind the head – which are typically reabsorbed as the fish matures, though traces may occasionally persist into adulthood.

Sexual dimorphism is subtle. Males tend to have a slightly thicker and wider anal fin compared to females, and mature females may appear somewhat fuller-bodied when carrying eggs. However, reliably sexing Banded Bichirs outside of breeding condition can be quite challenging.

Natural Habitat

Polypterus delhezi is endemic to the Congo River Basin in the Democratic Republic of the Congo, one of the most biodiverse freshwater ecosystems on the planet. Within this vast drainage, it inhabits a range of habitats including slow-moving river channels, vegetated backwaters, floodplain pools, and swampy marginal areas. The species shows a preference for areas with abundant cover, whether in the form of submerged wood, overhanging vegetation, rocky outcrops, or dense plant growth along the banks.

The waters in which the Banded Bichir is found are typically warm, soft to moderately hard, and slightly acidic to neutral in pH. Many of these habitats experience seasonal fluctuations in water level, temperature, and oxygen availability. During the wet season, extensive flooding connects the river channels to surrounding floodplain forests and marshes, vastly expanding the available habitat and providing access to rich feeding grounds. As waters recede during the dry season, bichirs may become concentrated in shrinking pools and channels.

The ability to breathe atmospheric air via modified swim bladders that function as primitive lungs is a crucial adaptation for survival in these environments. When dissolved oxygen levels drop – as frequently occurs in warm, stagnant floodplain pools – the Banded Bichir simply rises to the surface and gulps air. This adaptation also allows the species to survive brief periods out of water, provided the skin and gills remain moist. In the wild, bichirs have been observed moving short distances over damp ground between pools during periods of flooding or drought.

The substrate in typical Banded Bichir habitat tends to be a mix of mud, sand, and organic detritus such as fallen leaves and decomposing wood. Light levels are often low, filtered through overhanging vegetation or turbid water. Understanding these natural conditions is key to replicating an appropriate and stress-free captive environment.

Tank Size and Setup

A single Banded Bichir requires a minimum tank size of 300 litres, with a footprint that prioritises length and width over height. Bichirs are bottom-dwelling fish that spend the vast majority of their time on or near the substrate, so a long, wide tank of at least 120 cm in length and 45 cm in width is far more useful than a tall, narrow one. If keeping multiple bichirs or housing P. delhezi in a community alongside other large species, a tank of 450 litres or more is strongly recommended.

A tightly fitting lid is absolutely essential. Banded Bichirs are accomplished escape artists. Their ability to breathe air and their natural inclination to explore above the waterline means they will exploit even small gaps in the aquarium cover. Many bichir keepers have lost specimens to desiccation after the fish climbed out overnight through an uncovered filter intake slot or a gap around cable entry points. Every potential opening must be sealed or covered with mesh.

The substrate should be smooth sand or fine rounded gravel. Bichirs frequently rest directly on the bottom and may drag their bodies across the substrate while foraging, so sharp or coarse substrates can damage their soft undersides and pectoral fins, potentially leading to infections. A layer of fine sand, ideally in a natural tone, works best and also allows the fish to exhibit natural behaviours such as sifting through the substrate in search of food.

Provide plenty of hiding places using driftwood, bogwood, smooth rocks, PVC pipes, terracotta pots, or purpose-built caves. Bichirs are nocturnal by nature and appreciate having multiple sheltered retreats to rest in during daylight hours. A tank that offers ample cover will result in a less stressed, more confident fish that is more willing to emerge and be observed during feeding times.

Live plants are optional but can be included to provide additional cover and improve water quality. Robust species such as Anubias, Java Fern, and Bolbitis are good choices, as they can be attached to hardscape elements and are tough enough to withstand the occasional blundering of a large, active fish. Delicate stem plants are likely to be uprooted or damaged.

Lighting should be subdued. Bichirs are most active in dim conditions, and bright overhead lighting may cause them to remain hidden throughout the day. Using floating plants to diffuse surface light or choosing lower-intensity LED fixtures can encourage more natural behaviour and daytime activity.

Water Parameters

The Banded Bichir is a tolerant species in terms of water chemistry, accepting a fairly broad range of pH and hardness values. However, stability is more important than hitting a precise number. Sudden swings in pH or temperature are far more stressful and harmful than a slightly elevated or reduced value that remains consistent. Aim for a temperature in the mid-range of 25-27 °C for general maintenance.

While P. delhezi can tolerate moderately elevated nitrate levels thanks to its hardy constitution, this should not be used as an excuse for poor maintenance. Regular partial water changes of 25-30% on a weekly basis will help maintain low nitrate concentrations and replenish essential minerals. Use a quality dechlorinator when adding tap water, and try to match the temperature of replacement water to that of the tank to avoid thermal shock.

The ability of bichirs to breathe atmospheric air means they are somewhat more forgiving of low dissolved oxygen than many other fish. However, good oxygenation of the water column benefits the overall health of the aquarium ecosystem and should not be neglected. A modest surface agitation from the filter return or an airstone is sufficient.

Filtration and Equipment

Given the size of the Banded Bichir and its carnivorous diet, robust filtration is essential. Large predatory fish produce a substantial bioload, and uneaten food can quickly foul the water if not removed. An external canister filter rated for the tank volume – or preferably slightly over-rated – is the best choice for most setups. Look for a model that provides strong biological filtration capacity with ample media trays for ceramic rings, sintered glass, or other high-surface-area biomedia.

Mechanical filtration is equally important, as bichir tanks tend to accumulate particulate waste. Fine filter floss or sponge pads should be checked and replaced regularly to prevent clogging and maintain flow rate. Pre-filter sponges on intake pipes serve a dual purpose: they prevent juvenile or small tank mates from being drawn into the filter, and they capture coarse debris before it reaches the main filter media.

Flow rate in the tank should be moderate. While the Banded Bichir is not a weak swimmer, it naturally inhabits slow-moving or still waters and does not appreciate being buffeted by strong currents. Position the filter outlet so that flow is dispersed across the tank without creating a single powerful jet, or use a spray bar to distribute the current evenly.

A reliable heater is necessary to maintain tropical temperatures. A heater guard or an inline heater is recommended, as bichirs may rest against exposed glass heaters and sustain burns. Inline heaters, which sit within the canister filter pipework, eliminate this risk entirely and keep the equipment out of the display area.

Lighting needs are minimal. A standard LED fixture on a timer, set to provide 8-10 hours of light per day, is sufficient. If the tank contains live plants, choose a fixture appropriate for the plant species selected. For a bichir-only setup, a dimmer or lower-output light will encourage more natural activity patterns.

Diet and Feeding

The Banded Bichir is an opportunistic predator and scavenger in the wild, feeding on a varied diet that includes small fish, aquatic invertebrates, insect larvae, worms, and crustaceans. In captivity, replicating this dietary variety is important for long-term health, coloration, and vitality.

The staple diet can be built around high-quality sinking carnivore pellets or tablets, which provide a balanced nutritional profile including essential vitamins and minerals. Many bichir keepers find that their fish readily accept commercially prepared foods once accustomed to them, though newly acquired specimens may initially refuse dry foods and require live or frozen alternatives to stimulate feeding.

Frozen foods should form a regular part of the diet. Bloodworms, brine shrimp, Mysis shrimp, chopped prawns, mussel, and lance fish are all excellent choices. Earthworms – either live or chopped – are a particular favourite and are highly nutritious. Whitebait or small smelt, cut to appropriate sizes, can also be offered. Avoid feeding mammalian meats or fatty foods such as beef heart on a regular basis, as these can contribute to fatty liver disease over time.

Live foods, while not strictly necessary, are greatly appreciated and can be used to enrich the feeding experience. Live earthworms, blackworms, river shrimp, and appropriately sized feeder insects are all suitable. Avoid using feeder fish as a regular food source, as they carry a high risk of introducing parasites and diseases, and goldfish in particular contain thiaminase, which can lead to vitamin B1 deficiency with chronic use.

Bichirs are primarily nocturnal feeders and may be reluctant to eat during the day, especially in brightly lit tanks or when first introduced to a new environment. Offering food shortly after lights-out or during the evening hours often produces the best feeding response. As the fish becomes more settled, it will typically begin to associate the aquarist’s presence with food and may become bold enough to feed at any time of day.

Feed adult Banded Bichirs once daily or every other day, offering only as much food as can be consumed within a few minutes. Overfeeding is a common mistake with predatory fish and can lead to obesity, poor water quality, and associated health issues. Juveniles should be fed daily to support their growth.

Behaviour and Temperament

The Banded Bichir is a generally peaceful and slow-moving fish, spending much of the daytime resting in caves, under driftwood, or wedged into other hiding spots. As dusk approaches and lighting dims, it becomes considerably more active, emerging to patrol the substrate and investigate the tank in search of food. This crepuscular to nocturnal activity pattern is deeply ingrained and should be expected even in long-established aquarium specimens.

Despite their predatory nature, Banded Bichirs are not aggressive towards tank mates of similar or larger size. They are ambush predators rather than active pursuers, relying on stealth and their keen sense of smell to locate prey. Any fish small enough to fit into a bichir’s mouth will eventually be eaten – this is not aggression but simply the natural feeding behaviour of an opportunistic predator. Keeping P. delhezi with appropriately sized companions is therefore essential.

Bichirs are generally tolerant of conspecifics and can be kept in groups, provided the tank is large enough and offers sufficient hiding places to prevent territorial disputes over preferred resting spots. Occasional minor squabbles may occur, particularly during feeding, but these rarely result in injury thanks to the robust ganoid scale armour. A group of three or more tends to disperse aggression more evenly than keeping just two individuals together.

One of the most endearing behaviours of the Banded Bichir is its periodic trips to the surface to gulp air. This is entirely normal and not a sign of distress. Even in well-oxygenated water, bichirs will regularly breathe atmospherically, as their lungs supplement gill respiration. If, however, the fish is gasping at the surface continuously or displaying laboured breathing, water quality should be checked immediately.

Over time, Banded Bichirs often become remarkably tame, learning to recognise their keeper and approaching the front glass in anticipation of food. Some individuals will accept food directly from the aquarist’s fingers or from feeding tongs, adding a level of interaction rarely experienced with other fish species.

Tank Mates

Choosing appropriate tank mates for the Banded Bichir requires careful consideration of size, temperament, and habitat preferences. The golden rule is simple: if a fish can fit into the bichir’s mouth, it will eventually be eaten. Tank mates should therefore be of a robust size – ideally at least half the length of the bichir – and should not be overly aggressive or nippy, as the bichir’s relatively poor eyesight and slow movement can make it vulnerable to harassment from fast, aggressive species. Bottom-dwelling companions should be chosen with care, as competition for floor space and hiding spots can occasionally cause friction.

Good tank mates

• Severum – A peaceful, moderately sized cichlid that occupies the mid-water column and generally ignores bottom-dwelling bichirs.
• Featherfin Synodontis – A robust African catfish that shares similar water parameter preferences and is too large and armoured to be considered prey.
• Rope Fish – A fellow polypterid relative with similar care requirements and a peaceful disposition, making an excellent companion.
• Leopard Ctenopoma – An African bush fish that is compatible in temperament and water parameters, and is large enough to avoid predation.
• Silver Dollar – A peaceful, schooling species that remains in the upper water column and grows large enough to coexist safely with bichirs.
• Geophagus sveni – An eartheater cichlid that is generally peaceful and prefers the lower regions of the tank without being territorial enough to bother a bichir.
• Congo Tetra – When kept in a school and provided with sufficient space, these mid-water African tetras are generally large enough to avoid predation by a moderately sized Banded Bichir.
• Bristlenose Pleco – A hardy algae-eating catfish that stays out of the bichir’s way and is well-armoured enough to coexist peacefully.

Fish to avoid

• Neon Tetra – Far too small and will be treated as live food by any bichir.
• Guppy – Tiny and slow enough to be easily caught and consumed, making them entirely unsuitable companions.
• Oscar – While large enough to avoid predation, Oscars can become highly aggressive and may harass or injure a slower-moving bichir.
• Red-Tail Catfish – Grows far too large and will eventually consume the bichir as it matures.
• Tiger Barb – A notorious fin nipper that may target the bichir’s delicate finlets and pectoral fins.
• Mbuna Cichlids – Highly territorial and aggressive, these rift lake cichlids also require very different water chemistry from the Banded Bichir.
• Cherry Shrimp – Will be consumed almost immediately, as bichirs are natural invertebrate predators.
• Flowerhorn Cichlid – Extremely aggressive and territorial, posing a serious risk of injury to the relatively defenceless bichir.

Breeding

Breeding the Banded Bichir in captivity is achievable but challenging, and successful spawnings remain relatively uncommon in the home aquarium hobby. In the wild, breeding is linked to the onset of the rainy season, when rising water levels, increased water flow, and changes in water chemistry trigger spawning behaviour. Replicating these seasonal cues is key to encouraging captive reproduction.

Sexing adult Banded Bichirs requires close observation. The most reliable external indicator is the anal fin: in males, this fin is noticeably thicker, wider, and more fleshy than in females, forming a paddle-like structure that is used during spawning to cup and fertilise the eggs. Females tend to be slightly heavier-bodied when in breeding condition, with a visibly swollen abdomen.

To condition a breeding pair, provide a varied diet rich in high-quality proteins – live earthworms, prawns, and frozen foods – for several weeks. Gradually lower the water level in the tank by approximately 25-30%, then perform a large water change with slightly cooler, softer water to simulate the onset of the rainy season. Raising the temperature by one or two degrees over subsequent days can further stimulate spawning behaviour.

Courtship in Polypterus delhezi is a subtle but fascinating process. The male will pursue the female, swimming alongside her and occasionally nudging her flanks with his snout. During the culmination of courtship, the pair will swim closely together, and the male will cup his anal fin around the female’s vent to receive the eggs as they are released. He fertilises them externally within this cupped fin before scattering them over fine-leaved plants, moss, or spawning mops.

The eggs are small, adhesive, and somewhat scattered, sticking to vegetation and hardscape surfaces. Incubation takes approximately 3 to 4 days at 26-27 °C. The fry hatch with external gills – prominent, feathery structures that are unique to polypterid larvae – and are initially quite helpless. They will absorb their yolk sac over the first few days before becoming free-swimming.

Newly free-swimming fry can be fed infusoria, microworms, and newly hatched brine shrimp nauplii. Growth is relatively slow, and the fry are vulnerable to predation – including from their own parents – so rearing in a separate, well-filtered nursery tank is strongly recommended. As the fry grow, they can be gradually transitioned onto larger foods such as chopped bloodworms and crushed pellets. The external gills are typically reabsorbed by the time the juveniles reach 5-8 cm in length.

Common Diseases

The Banded Bichir is a robust species with a strong immune system, and well-maintained specimens rarely succumb to disease. However, like all aquarium fish, they can be affected by a range of health issues, particularly if water quality is allowed to deteriorate or if stress from inappropriate tank mates, inadequate cover, or poor nutrition weakens their defences.

Bacterial infections are among the most common ailments seen in captive bichirs. These typically manifest as reddened areas on the skin, fin erosion, ulcers, or cloudy patches. Poor water quality, physical abrasion from rough substrates, and injuries from aggressive tank mates are the usual predisposing factors. Treatment involves improving water conditions and, if necessary, administering appropriate antibacterial medications. Bichirs can be sensitive to certain medications, particularly those containing copper or formalin, so always check compatibility before dosing.

External parasites such as Ichthyophthirius multifiliis (white spot or ich) can occasionally affect bichirs, though their thick ganoid scales provide a degree of resistance. White spot presents as small, white, grain-like cysts on the skin and fins. Treatment with elevated temperature (to 30 °C) and half-dose salt therapy is often effective and safer for bichirs than full-strength chemical treatments.

Internal parasites, including roundworms and tapeworms, can be introduced through live feeder fish or wild-caught invertebrates. Symptoms may include weight loss despite a good appetite, bloating, or the passage of visible worms. Anti-parasitic medications such as praziquantel or levamisole can be used to treat internal infestations. Quarantining new specimens and avoiding feeder fish greatly reduces the risk.

Polypterid bloat is a condition occasionally reported in bichirs, characterised by pronounced abdominal swelling, lethargy, and loss of appetite. The exact causes can vary and may include bacterial infection, internal parasites, constipation, or organ dysfunction. Treatment depends on the underlying cause and may require a combination of fasting, Epsom salt baths, antibacterial medication, and improved diet.

Skin injuries and abrasions are relatively common in bichirs, particularly in tanks with rough substrates or sharp decor. These minor wounds usually heal quickly on their own provided water quality is good, but they can become infected if conditions are poor. Maintaining a smooth substrate and avoiding sharp-edged decorations are simple preventative measures.

FAQs

Do Banded Bichirs need to breathe air at the surface?

Yes, all bichirs possess modified swim bladders that function as primitive lungs, and they must periodically rise to the surface to gulp atmospheric air. This is entirely normal behaviour and will occur regardless of how well-oxygenated the water is. It is essential that the fish has unobstructed access to the water surface at all times. A tightly fitting lid is still necessary, but it must allow a small air gap between the water surface and the cover to permit this natural respiratory behaviour.

Can I keep a Banded Bichir with small fish like tetras or guppies?

No. The Banded Bichir is an opportunistic predator that will eat any fish small enough to fit into its mouth. While it is not an active pursuit predator, it will ambush small, slow, or sleeping fish during the night. Tank mates should be at least half the length of the bichir to be considered safe. Some keepers successfully maintain larger tetras such as Congo Tetras alongside moderately sized bichirs, but very small species are simply not compatible.

How fast do Banded Bichirs grow?

Growth rate depends heavily on diet, water quality, tank size, and temperature. Juveniles typically grow relatively quickly during their first year, potentially reaching 15-20 cm within 12 months under optimal conditions. Growth then slows considerably, and it may take two to three years for the fish to reach its full adult size of 30-35 cm. Consistent, high-quality feeding and regular water changes promote healthy growth.

Why does my Banded Bichir hide all day?

This is perfectly normal. Banded Bichirs are primarily crepuscular to nocturnal, meaning they are most active during twilight hours and at night. During the day, they prefer to rest in sheltered hiding spots such as caves, under driftwood, or among dense vegetation. Providing subdued lighting and feeding in the evening will encourage more visible activity. Over time, many bichirs become more confident and may begin to emerge during the day, particularly in anticipation of feeding.

Is the Banded Bichir suitable for a planted aquarium?

A Banded Bichir can be kept in a planted aquarium, but plant choices should be made carefully. The fish’s large size and bottom-dwelling habits mean that delicate or rooted stem plants are likely to be uprooted or damaged as the bichir moves around the tank. Hardy species such as Anubias, Java Fern, and Bolbitis, which can be attached to rocks or driftwood above the substrate level, are the most suitable options. Floating plants are also an excellent addition, as they help diffuse light and provide a more natural, shaded environment that the bichir will appreciate.

Related Guides

• Senegal Bichir – The most commonly kept bichir species and an excellent comparison point for those considering their first polypterid.
• Ornate Bichir – A larger and more boldly patterned relative that shares similar care requirements but demands a considerably bigger tank.
• Rope Fish – A closely related polypterid with a more elongated body shape, often kept alongside bichirs in large community setups.
• Featherfin Synodontis – A popular African catfish that makes an excellent companion for the Banded Bichir and thrives in similar conditions.
• Leopard Ctenopoma – Another Congo Basin native that pairs well with bichirs and offers a contrasting appearance and activity level.