Bichir
Polypterus sp.
Min Tank Size
280L
Adult Size
30.5 cm
Lifespan
15 years
About
Native to the slow-moving rivers, swamps, and floodplains of Africa, bichirs are genuinely ancient fish. Their lineage stretches back hundreds of millions of years, and you can tell just by looking at them. Armored in thick, interlocking ganoid scales and equipped with a series of distinctive dorsal finlets, they move through the water with a slow, serpentine crawl that looks almost reptilian.
Most hobbyists start with the Senegal bichir (P. senegalus), which tops out around 30cm and is one of the more manageable species. Others, like P. endlicheri or P. bichir, can push well past 60cm and need serious tank space.
Bichirs are obligate air breathers. They have a modified lung-like swim bladder and must reach the surface periodically, so a gap between the waterline and your lid is necessary but also a security risk since they are notorious escape artists. Water quality matters a lot, particularly for their gills, which are fragile and suffer fast in poor conditions. They prefer dimly lit tanks with plenty of cover: caves, driftwood, and shaded areas where they can hunker down during the day.
Feeding happens mostly at night. Meaty foods like earthworms, shrimp, fish fillets, and quality carnivore pellets work well once they're settled in. Wild-caught individuals sometimes take time to accept prepared foods. Tolerant of a fairly wide pH and hardness range, they're not fussy about chemistry as long as water stays clean and warm.
For anyone who wants something genuinely prehistoric in their living room, bichirs deliver like almost nothing else.
Water Parameters
Temperature
°CpH
GH
dGHKH
dKHSwimming Level
Flow Preference
Keeping multiple Bichir together
Bichir is mildly territorial. Small groups can work in spacious tanks with broken sightlines, but expect occasional squabbles.
Compatibility
Bichirs work best with fish that are clearly too large to be eaten and aren't so aggressive they'll harass a slow-moving bottom dweller. Oscars, large cichlids, rope fish, giant gourami, and big catfish like sailfin plecos are common successful companions. Avoid anything below roughly 10cm unless you're okay losing it. Avoid nippy species like tiger barbs or serpae tetras since bichirs don't retaliate but their elaborate fins can become targets. Rope fish are often listed as ideal tankmates because they occupy a similar niche and neither bothers the other. Fast-moving mid-water fish large enough to avoid predation also work well.
Commonly kept with
Species this one is most often paired withCommonly tried but avoid
Often paired, but shouldn't beCare Notes
The biggest beginner mistake is underestimating adult size, especially with species other than P. senegalus. A 100-liter tank that looks fine for a juvenile becomes a welfare problem fast. The second mistake is a loose or gap-filled lid: bichirs can and do escape, and they don't survive long out of water. Feeding only at night during the first few weeks helps newly introduced fish settle in. Biological filtration needs to be robust given their protein-heavy diet and high waste output. Watch for labored breathing or gill curling, both are early signs of water quality issues.
Behavior & Aggression
Bichirs aren't aggressive in a traditional sense. They don't chase or harass tankmates and rarely show territorial behavior toward other fish. Their threat is purely predatory: anything small enough to be engulfed will eventually disappear, often overnight. Two bichirs kept together generally coexist without issue, though competition for food or hiding spots can occasionally lead to nipping at fins or limbs. Size matching between bichirs is important since a large individual will not hesitate to attempt eating a significantly smaller one.
Things to Know
- Will eat any tankmate small enough to fit in its mouth
- Requires a tight-fitting lid, they escape easily
- Some species (P. endlicheri, P. bichir) exceed 60cm at adulthood
- Nocturnal feeder, daytime food refusal is normal
- Gill damage from poor water quality is a leading cause of death
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