Bichirs are some of the most unusual freshwater fish available to aquarists. With elongated bodies, armor-like scales, separate dorsal finlets, and broad paddle-shaped pectoral fins, these African fish look almost prehistoric as they slowly patrol the bottom of an aquarium.
The name bichir refers to several species in the genus Polypterus. Popular aquarium species include the Senegal Bichir (Polypterus senegalus), Delhezi or Barred Bichir (P. delhezi), Ornate Bichir (P. ornatipinnis), and Saddled Bichir (P. endlicherii).
Bichirs are hardy in many respects, but they are not small community fish. Depending on the species, adults may exceed 12 inches, and some have the potential to grow considerably larger. They are also opportunistic predators that will readily swallow smaller fish.
For aquarists who can provide a large aquarium, a tight-fitting lid, warm clean water, and appropriately sized tank mates, bichirs can be fascinating long-term pets.
🐠 Bichir Fish Care at a Glance
| Care Requirement | Bichir Fish |
|---|---|
| Scientific name | Polypterus spp. |
| Family | Polypteridae |
| Origin | Africa |
| Adult size | Roughly 12–30+ inches depending on species |
| Lifespan | Commonly 10–20+ years; potentially much longer |
| Minimum tank size | About 75 gallons for smaller species; much larger for large species |
| Temperature | Generally about 75–82°F, depending on species |
| pH | Approximately 6.0–8.0 |
| Water hardness | Soft to moderately hard |
| Temperament | Predatory but often relatively peaceful with fish too large to swallow |
| Diet | Carnivorous |
| Social needs | Can be kept singly or with compatible bichirs |
| Swimming level | Primarily bottom |
| Care level | Intermediate |
FishBase recognizes 13 species within Polypterus, with maximum recorded sizes ranging from under 12 inches in some species to well over 30 inches in others.
🦖 Why Do Bichirs Look Prehistoric?
Bichirs belong to an ancient lineage of ray-finned fishes and possess several anatomical features that look unlike those of typical aquarium fish.
Their bodies are covered with hard ganoid scales, producing an armored appearance.
Along the back is a row of separate dorsal finlets rather than one continuous dorsal fin. Each finlet contains a spine and gives the fish its characteristic saw-toothed silhouette.
Bichirs also have:
- Long cylindrical bodies
- Broad pectoral fins
- Large mouths
- Prominent nostrils
- Thick scales
- A powerful tail
- Functional lungs for breathing atmospheric air
These features combine to give bichirs their unmistakable ancient appearance.
🫁 Bichirs Can Breathe Air
One of the most fascinating things about bichirs is their ability to breathe atmospheric oxygen.
A bichir will periodically rise to the surface, take a gulp of air, and return to the bottom.
This is normal behavior.
The Senegal Bichir is documented as a facultative air-breather, an adaptation that allows it to inhabit swamps, lagoons, and other waters where dissolved oxygen can sometimes be low.
Because bichirs rely partly on atmospheric air, they must always have access to the water’s surface.
Never fill the aquarium in a way that prevents the fish from surfacing beneath the lid.
🌍 Where Do Bichirs Come From?
Bichirs are native to Africa.
Different species occur across large portions of the continent.
The Senegal Bichir, for example, occurs across West Africa and into the Nile system, while other species are associated with the Congo basin and additional African river systems.
Natural bichir habitats can include:
- Rivers
- Floodplains
- Swamps
- Lagoons
- Lakes
- Slow-moving waterways
- Muddy margins
- Heavily vegetated shallows
Many species spend considerable time close to the bottom or sheltered among vegetation and submerged structure.
✨ Popular Bichir Species
Several bichirs regularly appear in the aquarium hobby.
Senegal Bichir
The Senegal Bichir (Polypterus senegalus) is one of the most commonly kept species.
It usually has a relatively plain gray, olive, or beige body and is often recommended as a first bichir because captive specimens are readily available.
It is also sometimes called the Gray Bichir.
Delhezi Bichir
The Delhezi or Barred Bichir (Polypterus delhezi) has a striking pattern of dark vertical bars.
FishBase records the species at up to about 44 centimeters, or roughly 17 inches, in total length.
Ornate Bichir
The Ornate Bichir (Polypterus ornatipinnis) is one of the most beautifully patterned members of the genus.
Its body is covered with contrasting dark and pale markings, but it is also a substantial fish. FishBase reports a maximum total length of about 60 centimeters, or roughly 24 inches.
Saddled Bichir
The Saddled Bichir (Polypterus endlicherii) is another large species.
It develops a broad head, heavy body, and dramatic dark saddles across its back. FishBase records individuals exceeding 25 inches in standard length.
📏 How Big Do Bichirs Get?
Adult size varies tremendously by species.
This is one reason it is important to know the scientific name of the fish before purchasing it.
Some commonly encountered bichirs reach around:
- 12–18 inches
- 18–24 inches
- More than 24 inches
FishBase lists maximum recorded lengths across Polypterus ranging from approximately 26.7 centimeters for P. mokelembembe to 97 centimeters for P. congicus.
Not every aquarium specimen will reach the maximum recorded wild size, but these figures illustrate why bichirs should never be purchased on the assumption that the small juvenile in the store will remain that size.
🏡 Bichir Tank Size
Tank size must be matched to the species.
For smaller commonly kept bichirs such as captive-bred Senegal Bichirs, 75 gallons is a reasonable practical starting point for an adult, with larger aquariums preferable.
Larger species may eventually need:
- 125 gallons
- 180 gallons
- 240 gallons
- Or even larger custom aquariums
Floor space is particularly important.
Bichirs spend much of their lives near the bottom, so a long, wide aquarium is more useful than an unusually tall tank containing the same volume.
When choosing a tank, plan for the fish’s adult size, not its current size.
🚪 Bichirs Are Escape Artists
A tight-fitting lid is absolutely essential.
Bichirs are powerful fish capable of pushing through gaps and escaping from surprisingly small openings.
Inspect spaces around:
- Filters
- Hoses
- Heater cords
- Airline tubing
- Feeding openings
- Aquarium corners
Cover them securely.
At the same time, leave an air space between the water surface and lid so the bichir can breathe normally.
An escaped bichir may survive outside water longer than an ordinary aquarium fish because of its air-breathing adaptations, but that does not make escape safe.
🌡️ Bichir Water Temperature
Most aquarium bichirs prefer warm tropical water.
A general range of approximately:
75–82°F
works for many commonly kept species.
However, requirements vary.
FishBase lists the Senegal Bichir at approximately 77–82°F, while the Ornate Bichir is associated with similarly warm tropical conditions.
Use a reliable heater and thermometer and avoid sudden changes.
Tank mates must also be comfortable at the same temperature.
💧 Bichir pH and Water Parameters
Many bichirs are reasonably adaptable to water chemistry when conditions remain stable.
For the commonly kept Senegal Bichir, FishBase lists approximately:
- pH: 6.0–8.0
- Hardness: 5–19 dH
- Temperature: 77–82°F
In the aquarium, prioritize:
- Ammonia: 0 ppm
- Nitrite: 0 ppm
- Nitrate: Controlled with regular maintenance
- Stable pH
- Stable temperature
Do not continually manipulate water chemistry simply to reach one supposedly perfect number.
🧹 Water Quality and Maintenance
Bichirs are often described as hardy, but their large adult size and carnivorous diet can produce considerable waste.
A mature bichir aquarium needs:
- Strong biological filtration
- Regular partial water changes
- Routine water testing
- Substrate cleaning
- Removal of uneaten food
- Sensible stocking
Large pieces of meat left decomposing in the tank can quickly damage water quality.
Ammonia and nitrite should remain at 0 ppm.
If you’re still learning aquarium cycling, see How to Set Up Your First Aquarium: A Beginner’s Guide.
🔄 Filtration for Bichirs
Strong filtration is highly recommended.
Suitable systems include:
- Large canister filters
- Sump filtration
- Multiple hang-on-back filters for smaller setups
- Supplemental sponge filtration
The filter should be sized for the actual biological load rather than simply the aquarium’s gallon rating.
Bichirs do not need to be blasted by powerful current.
Provide good filtration and oxygenation while still creating calmer areas along the aquarium floor.
🏖️ Best Substrate for Bichirs
Fine sand is an excellent choice.
Bichirs spend much of their time resting and moving along the bottom.
A soft substrate allows natural exploration while reducing the chance of abrasions.
Suitable options include:
- Fine aquarium sand
- Smooth rounded gravel
- Bare-bottom setups
Avoid sharp gravel and jagged rocks.
Dark sand can also provide a striking background for lighter-colored bichirs.
🪵 How to Set Up a Bichir Aquarium
A bichir aquarium should contain plenty of floor space along with secure hiding places.
Useful additions include:
- Large driftwood
- Smooth rocks
- Caves
- Large aquarium-safe tubes
- Robust live plants
- Shaded areas
- Open sandy sections
Make sure every cave remains large enough as the fish grows.
A hiding place that is perfect for a six-inch juvenile may become a dangerous trap for a 15-inch adult.
Secure heavy décor so a powerful bichir cannot undermine or shift it.
🌿 Can Bichirs Live With Plants?
Yes.
Bichirs generally do not deliberately eat aquarium plants.
Good options include:
- Anubias
- Java fern
- Amazon swords
- Vallisneria
- Java moss
- Large Cryptocoryne species
The challenge is physical disturbance.
A large bichir can push through plants or accidentally uproot them while searching for food.
Attaching Anubias or Java fern to heavy rocks or driftwood can work especially well.
For more ideas, see Top 30 Easy-to-Grow Live Aquarium Plants for Freshwater Tanks.
🌙 Are Bichirs Nocturnal?
Bichirs are often most active during the evening and nighttime.
Some species hunt primarily after dark; FishBase specifically describes the Ornate Bichir as primarily nocturnal.
During the day, a bichir may:
- Rest under driftwood
- Sit quietly on the substrate
- Shelter inside caves
- Remain beneath plant cover
As the lights dim, the fish often becomes much more active.
Many captive bichirs also learn feeding routines and readily emerge during daylight when food appears.
🍽️ What Do Bichirs Eat?
Bichirs are primarily carnivorous predators.
Wild Senegal Bichirs consume foods including:
- Insects
- Crustaceans
- Mollusks
- Frogs
- Fish
Aquarium bichirs can be fed a varied diet containing:
- Quality sinking carnivore pellets
- Frozen shrimp
- Mysis shrimp
- Earthworms
- Chopped prawns
- Mussel meat
- Appropriate frozen fish foods
- Other suitable meaty foods
Many captive-bred individuals readily learn to accept sinking pellets.
🚫 Should You Feed Bichirs Feeder Fish?
Routine use of live feeder fish is unnecessary and generally best avoided.
Feeder fish can introduce:
- Parasites
- Bacteria
- Disease
- Poor nutrition
Some commonly sold feeder fish are also nutritionally unsuitable as a staple.
A bichir can thrive on quality prepared foods supplemented with appropriately sourced frozen or fresh aquatic foods.
There is no need to make live fish the foundation of its diet.
🥩 How Often Should You Feed a Bichir?
Young bichirs generally need food more frequently than mature adults.
Juveniles can be fed modest meals once or twice daily depending on size and growth.
Adults can often be fed once daily or several substantial meals per week, depending on body condition and food type.
The goal is a healthy, well-muscled fish rather than an overfed one.
Remove food that remains uneaten.
👃 How Do Bichirs Find Food?
Bichirs possess an excellent sense of smell.
Their nostrils are prominent, and they can locate food even in relatively dim conditions.
You may see a bichir:
- Raise its head.
- Move its nostrils around the substrate.
- Follow the scent of food.
- Suddenly grab the meal.
Their eyesight is useful, but scent plays an especially important role when feeding after dark.
🐟 Will Bichirs Eat Other Fish?
Yes.
This is the fundamental rule of bichir compatibility:
If another fish can fit inside the bichir’s mouth, assume it may eventually be eaten.
A bichir does not need to be outwardly aggressive to be dangerous to smaller tank mates.
A fish that peacefully swims beside a young bichir for months may disappear once the bichir grows large enough to swallow it.
Choose tank mates based on adult sizes, not their current size.
🤝 Bichir Tank Mates
Suitable companions are generally robust fish too large to swallow and not aggressive enough to continually harass the bichir.
Depending on aquarium size and species, possibilities can include appropriately selected:
- Large cichlids
- Large catfish
- Silver dollars
- Larger peaceful or semi-aggressive fish
- Other similar-sized bichirs
An Oscar Fish is one example sometimes considered for large predator communities, although both species require substantial space and individual temperament must always be considered.
You can explore additional species in The Top 50 Freshwater Fish for Aquariums.
🚫 Bichir Tank Mates to Avoid
Avoid fish that are:
- Small enough to swallow
- Extremely aggressive
- Persistent fin-nippers
- Likely to attack slow bottom dwellers
- Able to fit a bichir into their own mouth
- Incompatible with warm freshwater conditions
Small fish such as:
- Neon Tetras
- Guppies
- Small rasboras
- Small danios
- Tiny catfish
should generally be viewed as potential prey.
Shrimp and many small snails may also be eaten.
🦈 Can Bichirs Live With Other Bichirs?
Often, yes.
Bichirs are not schooling fish, but compatible individuals can frequently coexist in a sufficiently large aquarium.
The most important considerations are:
- Similar size
- Adequate floor space
- Multiple hiding places
- Sufficient food
- Species compatibility
Avoid combining a tiny bichir with a dramatically larger individual capable of swallowing it.
Feeding multiple bichirs in separate areas can also reduce competition.
🐟 Bichir Behavior
Bichirs have a calm but distinctly predatory personality.
Common behaviors include:
- Resting on the bottom
- Walking or pushing along with their pectoral fins
- Cruising slowly through the aquarium
- Hiding beneath driftwood
- Emerging at feeding time
- Smelling the substrate for food
- Rising to breathe air
- Becoming more active after dark
They often become surprisingly responsive to their keeper.
A well-established bichir may emerge from hiding as soon as someone approaches the aquarium because it associates people with food.
🚶 Do Bichirs Walk?
Sort of.
Their broad, muscular pectoral fins allow them to push and maneuver along the bottom in a manner that can look almost like walking.
Juvenile bichirs are particularly fascinating because they temporarily possess external gills, another feature that contributes to their unusual amphibian-like appearance.
FishBase documents external gills in juvenile Senegal Bichirs.
🫧 Why Does My Bichir Keep Going to the Surface?
Occasional trips to the surface are completely normal.
Bichirs breathe atmospheric air using their lungs.
A healthy fish may rise, gulp air, and immediately return to the bottom.
However, unusually frantic behavior or frequent surface activity accompanied by distress in other fish should prompt you to test:
- Ammonia
- Nitrite
- Temperature
- Oxygenation
- Filter operation
Normal air breathing should not be confused with an aquarium-wide water-quality emergency.
🥚 Breeding Bichirs
Bichirs can breed in captivity, although reproduction is not as straightforward as breeding guppies or many cichlids.
Seasonal environmental changes can influence reproductive behavior in the wild.
FishBase reports that spawning in Polypterus delhezi, for example, is associated with the rainy season.
During courtship, a male follows and interacts closely with the female.
Eggs are scattered among vegetation or suitable spawning material.
The adults do not provide the kind of extended parental care seen in many cichlids.
👶 Baby Bichirs and External Gills
Juvenile bichirs are especially remarkable.
Young fish develop external gills, giving them an appearance somewhat reminiscent of an amphibian larva or axolotl.
As they mature, these external gills eventually disappear.
FishBase records juvenile Senegal Bichirs retaining external gills at lengths of up to approximately 10 centimeters.
This developmental stage is one of the most extraordinary features of the family.
♀️ Male vs. Female Bichir
Sexing mature bichirs is possible by examining the anal fin.
Male Bichir
Adult males generally develop:
- A broader
- Thicker
- More muscular anal fin
Female Bichir
Females generally have:
- A narrower anal fin
- A fuller body when carrying eggs
These differences become much easier to recognize after the fish reaches sexual maturity.
Juvenile bichirs can be difficult to sex reliably.
🩺 Common Bichir Health Problems
Bichirs are hardy fish, but poor conditions can still cause serious health problems.
Watch for:
- Loss of appetite
- Skin lesions
- Cloudy eyes
- Abnormal swelling
- Rapid breathing
- Unusual lethargy
- Weight loss
- Redness
- White spots
- Difficulty swimming
Before assuming that medication is necessary, test:
- Ammonia
- Nitrite
- Nitrate
- Temperature
- pH
Also inspect the fish for injuries from sharp decorations or aggressive tank mates.
Quarantining new fish before adding them to an established predator aquarium can reduce the risk of introducing disease.
🛡️ Are Bichirs Hardy?
Generally, yes.
Their air-breathing ability and adaptable physiology allow them to tolerate conditions that might challenge some more delicate fish.
That does not make poor aquarium care acceptable.
They still need:
- A cycled tank
- Clean water
- Suitable temperature
- Appropriate food
- Adequate space
- Safe decorations
- Compatible tank mates
Their hardiness should be viewed as resilience—not permission to neglect maintenance.
⏳ How Long Do Bichirs Live?
Bichirs can be exceptionally long-lived.
A lifespan of 10–20 years or more is entirely possible, depending on species and husbandry.
FishBase reports captive longevity of 34 years or more for the Senegal Bichir.
That makes a bichir a very serious long-term commitment.
The tiny juvenile purchased today could still be living in your aquarium decades from now.
🌟 Are Bichirs Good for Beginners?
Bichirs are generally better suited to intermediate aquarists.
They are physically hardy, but successful ownership requires understanding:
- Large adult size
- Predator compatibility
- Escape prevention
- Large aquarium filtration
- Feeding large carnivorous fish
- Long-term housing requirements
- Water quality
A beginner with a properly researched 75-gallon-or-larger setup could successfully keep a smaller bichir species.
However, bichirs are not good impulse purchases for someone setting up a small first aquarium.
🛒 What to Know Before Buying a Bichir
Before bringing one home, determine the exact species.
Do not purchase a fish labeled simply “bichir” without knowing what it is likely to become.
Ask:
- What species is it?
- How large can it grow?
- Is it captive-bred or wild-caught?
- What is it currently eating?
- What tank size will the adult need?
- Do I have compatible tank mates?
- Can I keep the aquarium completely escape-proof?
The difference between bichir species can amount to many inches of adult length and a dramatically different long-term aquarium requirement.
❤️ Are Bichirs Worth Keeping?
For the right aquarist, absolutely.
Few freshwater fish have the presence of a bichir. Their armored scales, dragon-like dorsal finlets, broad pectoral fins, slow stalking movements, air-breathing behavior, and remarkable evolutionary history make them unlike almost anything else in a home aquarium.
They are also surprisingly engaging fish once settled. A bichir may spend hours resting quietly beneath driftwood and then suddenly emerge as soon as its keeper enters the room.
But these prehistoric-looking predators deserve to be planned for properly.
Choose the species carefully, provide a spacious aquarium, use a secure lid, maintain strong filtration, offer a varied carnivorous diet, and never combine them with fish small enough to swallow.
If you can meet those requirements for many years, a bichir can become one of the most extraordinary freshwater fish you will ever keep.
🔗 Related Articles
- The Top 50 Freshwater Fish for Aquariums
- Oscar Fish
- Freshwater Aquarium Fish
- How to Set Up Your First Aquarium: A Beginner’s Guide
