Bichir Fish Tank Mates – The Ultimate Compatibility Guide For A Harmon
Keeping prehistoric-looking “living fossils” like the Polypterus is one of the most rewarding experiences a hobbyist can have. We all agree that their dragon-like appearance and undulating swimming style make them the undisputed stars of any large aquarium.
However, finding the right bichir fish tank mates can feel like a high-stakes guessing game if you don’t know their unique social “rules.” I promise that by the end of this guide, you will have a clear, safe, and exciting list of compatible neighbors for your bichir.
We will explore the best species for different tank sizes, how to avoid common predatory mishaps, and how to set up your environment for long-term success. Don’t worry—creating a thriving community with these ancient predators is entirely achievable with a bit of expert planning!
Understanding the Unique Temperament of Your Bichir
Before we dive into the specific species, we need to understand what makes a bichir tick. Bichirs are nocturnal bottom-dwellers with a specialized respiratory system that allows them to breathe atmospheric air.
While they look like aggressive monsters, most species are actually quite peaceful—provided their tank mates don’t fit in their mouths. They are opportunistic carnivores, meaning if it looks like food and moves like food, they will eventually try to eat it.
The key to a successful community is balancing their “low-energy” lifestyle with fish that won’t nip at their sensitive external gills or dorsal finlets. Let’s look at the best candidates that can hold their own alongside these magnificent creatures.
The “Mouth Rule” of Compatibility
The most important rule in the monster fish hobby is the “If it fits, I sits” rule—or in this case, “If it fits, I eat.” Bichirs have surprisingly wide mouths and can swallow fish that look much larger than you might expect.
Always choose tank mates that are at least two-thirds the length of your bichir to ensure they aren’t viewed as a midnight snack. This is especially important during the night when your bichir is most active and other fish are resting.
Top 10 Bichir Fish Tank Mates for a Healthy Community
Selecting bichir fish tank mates requires finding fish that occupy the middle and upper water columns. Since bichirs spend most of their time prowling the substrate, you want neighbors that won’t crowd their personal space.
Here are ten species that I have personally found to be excellent companions for various Polypterus species.
1. Oscars (Astronotus ocellatus)
Oscars are perhaps the most popular companions for larger bichir species like the Endlicheri or Ornatipinnis.
They are intelligent and robust, usually ignoring the bichir as it slithers along the bottom.
Just ensure you have a large enough tank (at least 75-100 gallons) to handle the massive bio-load these two species produce. Oscars are messy eaters, so you’ll need to keep up with your water changes to keep the bichir’s sensitive skin healthy.
2. Silver Dollars (Metynnis argenteus)
If you want activity in the mid-water column, Silver Dollars are an outstanding choice.
They are fast-moving, peaceful schoolers that are far too large and thin to be eaten by most bichirs.
Their shimmering scales provide a beautiful contrast to the earthy tones of a bichir. Keep them in groups of five or more to reduce stress and encourage natural schooling behavior.
3. Severum Cichlids (Heros efasciatus)
Severums are often called the “poor man’s Discus,” but they are much hardier and better suited for a bichir tank.
They have a mellow temperament compared to other South American cichlids, making them great neighbors.
They stay large enough to avoid being eaten but are rarely aggressive enough to bother the bichir. The Gold or Turquoise varieties look stunning against a dark sand substrate.
4. Ropefish (Erpetoichthys calabaricus)
Ropefish are actually close relatives of the bichir and share many of the same care requirements.
They are incredibly peaceful and enjoy the company of their own kind as well as other Polypterids.
Just be warned: Ropefish are the ultimate escape artists! You must have a tight-fitting lid with every single gap plugged, or you will find them on the floor.
5. Jack Dempsey Cichlids (Rocio octofasciata)
For a slightly more “rough and tumble” tank, the Jack Dempsey is a solid contender.
They are tough enough to stand their ground but generally don’t go out of their way to harass bottom-dwellers.
I recommend adding the Jack Dempsey to the tank after the bichir has established its territory. This helps prevent the cichlid from becoming overly territorial over the entire substrate.
6. Large Datnoids (Datnioides microlepis)
Datnoids, or Tiger Fish, are majestic predators that occupy the middle of the tank.
They have a deep body shape that makes them nearly impossible for a bichir to swallow.
They are slow growers, so ensure the size discrepancy isn’t too large when you first introduce them. A Datnoid hovering over a piece of driftwood with a bichir underneath is a classic “monster tank” aesthetic.
7. Blood Parrot Cichlids
While controversial to some, Blood Parrots are actually excellent tank mates due to their physical limitations.
Their mouths usually don’t close fully, meaning they cannot deliver a damaging bite to a bichir.
They are colorful, active, and provide a lot of “personality” to the aquarium. They are also quite hardy and can tolerate the same water parameters as most bichir species.
8. Giant Danios (Devario aequipinnatus)
If you have a smaller bichir species like the Senegalus (Senegal Bichir), Giant Danios are a great dither fish.
They are extremely fast and stay near the surface, keeping them out of the bichir’s strike zone.
Always keep them in a school of at least six to ensure they feel secure in a tank with larger predators. Their constant movement can also help bring “shy” bichirs out of their hiding spots.
9. Knife Fish (Black Ghost or Clown)
Knife fish are oddballs that share the bichir’s nocturnal lifestyle and unique look.
The Black Ghost Knife is generally peaceful, though it does require its own “tube” or hiding spot.
Clown Knives get massive (up to 3 feet), so only pair them with the largest bichir species like the Congicus. Both species appreciate the low-light environments that bichirs thrive in.
10. Large Plecos (Loricariidae)
A large Common Pleco or a Sailfin Pleco can work, but you must be very careful.
Some Plecos develop a taste for the slime coat of the bichir and may “latch on” at night.
If you notice any circular marks on your bichir, remove the Pleco immediately. However, in many cases, a well-fed Pleco will stick to algae and leftover pellets without bothering anyone.
Why Size and Variety Matter for Bichir Compatibility
When searching for bichir fish tank mates, you have to distinguish between “Upper Jaw” and “Lower Jaw” bichirs. Upper Jaw species (like the Senegal or Delhezi) usually stay under 12-14 inches and are more active.
Lower Jaw species (like the Endlicheri or Congicus) can reach 24-30 inches and are much more predatory. A tank mate that works for a Senegal might be a snack for an Endlicheri within a week.
Always research the maximum adult size of your specific bichir species before buying neighbors. It’s much better to buy fish that will grow with your bichir rather than trying to introduce small fish later.
Species to Avoid: Keeping Your Bichirs Safe
Not every large fish is a good fit, and some small fish are outright dangerous for bichirs to ingest. I have seen many hobbyists lose their prized bichirs because they chose the wrong companions.
Avoid African Cichlids from the Rift Lakes (Mbuna), as they are far too aggressive and will nip finlets. They also require a much higher pH than the slightly acidic to neutral water bichirs prefer.
Avoid small Tetras, Guppies, and Shrimp, as these will be hunted and eaten almost immediately. Even if you don’t mind the loss, some small fish have sharp dorsal spines (like Corydoras) that can get stuck in a bichir’s throat.
Lastly, avoid very aggressive “wet pets” like Flowerhorns or Red Devils. These fish are often too territorial to share a tank with anything and will relentlessly bully a peaceful bichir.
Setting Up the Perfect Community Environment
To ensure your bichir fish tank mates all get along, the aquarium layout is absolutely critical. Bichirs are territorial about their “hiding spots,” so providing plenty of caves and driftwood is a must.
Use a soft sand substrate rather than sharp gravel, as bichirs can easily scrape their bellies. Sand also makes it easier for the bichir to “sift” for food without swallowing dangerous rocks.
I highly recommend adding floating plants or low-light plants like Anubias and Java Fern. This creates a dappled light effect that makes the bichir feel secure enough to explore during the day.
Filtration and Water Flow
Bichirs and their large tank mates produce a significant amount of waste (ammonia and nitrites). You will need heavy-duty filtration, such as a large canister filter or a sump system.
However, try to keep the water flow moderate rather than turbulent. Bichirs aren’t the strongest swimmers and prefer calmer waters where they can easily surface for air.
Feeding a Multi-Species Tank with Bichirs
One of the biggest challenges is making sure your bichir gets enough food. Faster tank mates like Silver Dollars or Oscars will often gobble up everything before it hits the bottom.
I recommend feeding your mid-water fish first to distract them at the surface. Then, use a feeding tube or long tweezers to deliver sinking carnivore pellets or frozen foods directly to the bichir.
Feeding your bichir just before you turn the lights out for the night is another great strategy. Since they are nocturnal, they will have a competitive advantage in the dark while the other fish are “sleeping.”
Frequently Asked Questions About Bichir Tank Mates
Can bichirs live with goldfish?
I strongly advise against this. Goldfish prefer cooler water, while bichirs are tropical.
Additionally, goldfish produce a lot of slime and waste, and a large bichir will eventually try to eat a goldfish.
Are bichirs aggressive toward their own kind?
Generally, no! Bichirs are quite social with other Polypterus species of similar size.
They will often “pile up” in a single cave, a behavior hobbyists affectionately call a “bichir puddle.”
Can I keep shrimp with my bichir?
Only if you want the shrimp to be an expensive dinner.
Bichirs are excellent hunters of crustaceans and will clear out a shrimp colony in a single night.
What is the minimum tank size for a bichir community?
For the smaller Senegal bichir, a 55-gallon tank is the absolute minimum for a community.
For larger species, you should look at 125 gallons or more to provide enough floor space.
Conclusion: Success with Your Prehistoric Community
Finding the right bichir fish tank mates is all about balancing size, temperament, and tank zones. By choosing robust, peaceful-to-semi-aggressive fish that occupy the upper water levels, you create a dynamic display.
Remember to prioritize a sand substrate, plenty of hiding spots, and a secure lid to keep your fish happy. Keeping a bichir community is a journey into the ancient past of fish evolution—and it’s a journey worth taking.
If you stick to the “mouth rule” and provide high-quality filtration, your bichir will thrive for decades. Happy fish keeping, and enjoy the majestic sight of your very own “underwater dragons”!
