Bichir Fish Tank Size – The Ultimate Guide To Choosing The Right Home

Keeping a bichir is like owning a literal piece of natural history. These prehistoric-looking “dinosaur eels” are hardy, fascinating, and full of personality.

If you are reading this, you likely agree that these fish are some of the most unique additions to the hobby. I promise to help you navigate the often-confusing world of tank dimensions.

In this guide, we will preview everything from species-specific needs to why “footprint” is the most important word in your vocabulary. Finding the correct bichir fish tank size is the first step to success.

Understanding the Unique Biology of Bichirs

Before we dive into the numbers, we need to understand why these fish have such specific housing requirements. Bichirs belong to the family Polypteridae, which is one of the oldest lineages of ray-finned fish.

They possess primitive lungs, allowing them to breathe atmospheric air. This means they must have easy access to the water’s surface to gulp air occasionally.

Because they are bottom-dwellers, they spend most of their time prowling the substrate. This behavior dictates the shape of the tank you should buy for your new aquatic friend.

Upper Jaw vs. Lower Jaw Bichirs

In the hobby, we generally categorize these fish into two groups: “Upper Jaw” and “Lower Jaw” species. This distinction is vital for determining the bichir fish tank size they will eventually need.

Upper Jaw species, like the Senegal or Delhezi, tend to stay smaller and are more active. Lower Jaw species, such as the Endlicheri, are true monsters that can reach massive lengths.

Knowing which group your fish belongs to will prevent the heartbreak of having to rehome a fish that has outgrown its environment. Let’s break down the sizes you’ll actually encounter.

Bichir Fish Tank Size: Specific Recommendations by Species

Choosing the right volume is about more than just the “gallons” on the label. It is about providing enough turning room for a long, muscular body.

Here are the most common species and the minimum footprints they require to thrive as adults. Don’t worry—we’ll help you find the perfect fit!

The Senegal Bichir (Polypterus senegalus)

Often called the “Dinosaur Eel,” the Senegal is the most common species for beginners. They typically grow to about 10–12 inches in a home aquarium.

For a single Senegal, a 40-gallon breeder tank is the absolute minimum. The 36-inch length provides enough room for them to swim and explore comfortably.

However, a 55-gallon or 75-gallon tank is even better. This extra width allows them to turn around without constantly bumping into the glass.

The Delhezi Bichir (Polypterus delhezi)

The Delhezi, or “Barred Bichir,” is a stunning species with beautiful markings. They stay relatively small, usually reaching around 12–14 inches.

Because they are slightly bulkier than Senegals, a 75-gallon tank is the gold standard here. The 18-inch depth (front to back) is perfect for their body length.

Keeping them in anything narrower can lead to spinal deformities or stress. We want our fish to be happy and straight-backed!

The Ornate Bichir (Polypterus ornatipinnis)

Now we are moving into the larger territory. The Ornate Bichir is arguably the most beautiful, but it can reach up to 24 inches in length.

For an Ornate, you are looking at a 120-gallon to 180-gallon tank. They need a very wide footprint to accommodate their impressive size.

I always recommend at least a 24-inch wide tank for these beauties. It ensures they can exhibit their natural hunting behaviors without restriction.

The Saddled Bichir (Polypterus endlicheri)

The “Endli” is a Lower Jaw giant. These fish can easily reach 24–30 inches and are incredibly thick-bodied predators.

For an adult Endlicheri, a 180-gallon tank is the starting point. Many dedicated keepers eventually move them to custom 240-gallon to 300-gallon setups.

It might sound daunting, but watching a massive Endlicheri glide across a large tank is a sight to behold. It is worth every bit of the effort!

Why Floor Space Matters More Than Depth (The Footprint Rule)

When researching the ideal bichir fish tank size, you must prioritize the “footprint.” This refers to the length and width of the tank bottom.

Bichirs are not “vertical” swimmers like Angelfish or Discus. They are elongated, heavy-bodied fish that live on the floor of the river.

A tall, narrow tank is essentially useless for a bichir. They need horizontal space to move, hunt, and rest on the sand.

The “Turning Room” Calculation

A good rule of thumb is that the width of the tank should be at least 1.5 times the length of the fish. This allows for a natural 180-degree turn.

If your fish is 12 inches long, an 18-inch wide tank is perfect. If they are 24 inches long, you need a 36-inch wide monster tank.

Always look for “Breeder” or “Wide” tank models. These are designed with a larger surface area at the bottom, which is exactly what a bichir loves.

Essential Tank Features for Bichirs

Once you have the size figured out, we need to talk about the “guts” of the setup. A big tank is only half the battle for a healthy fish.

Bichirs have specific environmental needs that complement their tank size. Let’s look at how to deck out their new home.

The Importance of a Secure Lid

I cannot stress this enough: Bichirs are legendary escape artists. They can and will find the smallest gap in your lid and jump out.

Because they can breathe air, they can survive for a while on the floor. However, it is a traumatic experience that often ends poorly.

Invest in a heavy-duty, weighted lid. Use glass tops and ensure there are no gaps around heaters or filter pipes.

Substrate Choice: Sand vs. Gravel

In the wild, these fish live over muddy or sandy riverbeds. In the aquarium, smooth sand is the best choice for their delicate bellies.

Gravel can be dangerous. Bichirs are “gulp” feeders, and they can accidentally ingest large pieces of gravel, leading to fatal impaction.

Sand also allows them to exhibit natural behaviors. They love to rest partially buried or sift through the top layer for food.

Filtration for Messy Eaters

Bichirs are carnivores that produce a significant amount of waste. They eat high-protein foods like tilapia, shrimp, and pellets.

To keep your bichir fish tank size manageable, you need over-sized filtration. I recommend using large canister filters or a sump system.

Aim for a filter that turns over the entire volume of the tank at least 5 to 10 times per hour. This keeps the water crystal clear and nitrate levels low.

Common Mistakes When Sizing a Bichir Aquarium

Even experienced hobbyists can make mistakes when it comes to these prehistoric fish. Let’s look at a few pitfalls to avoid.

One common error is buying a “grow-out” tank with no plan for the future. Bichirs grow surprisingly fast in their first year of life.

If you start a Senegal in a 20-gallon tank, you will likely need to upgrade in less than six months. It is often cheaper to buy the “forever tank” from the start.

Underestimating Adult Size

Many fish stores sell “cute” 3-inch bichirs. Don’t let their small size fool you!

Always research the specific species before buying. That tiny Polypterus endlicheri will become a two-foot-long predator before you know it.

If you aren’t prepared for a 180-gallon tank in the future, stick with the smaller Upper Jaw species like the Senegal or Albino varieties.

Ignoring the “Air Gap”

Because bichirs breathe atmospheric air, you cannot fill the tank to the very brim if you have a tight lid. They need a small pocket of air at the top.

Leave about 1–2 inches of space between the water surface and the lid. This allows them to take a quick gulp of air and head back to the bottom.

If they cannot reach the surface, they can actually drown. It sounds strange for a fish, but it is a vital part of their biology!

Growth Rates: Will Your Bichir Outgrow Its Tank?

Bichirs are generally long-lived fish, often reaching 10 to 20 years in captivity. Their growth is most rapid during the first 12 to 18 months.

A Senegal Bichir might grow an inch per month under ideal conditions. Proper bichir fish tank size ensures this growth isn’t stunted.

Stunting happens when a fish is kept in a tank that is too small. This leads to internal organ damage and a shortened lifespan.

By providing a large environment early on, you encourage healthy muscle development. A well-grown bichir is a powerful, thick, and impressive animal.

Bichir Tank Mate Compatibility and Space Needs

Bichirs are generally peaceful toward fish they cannot fit in their mouths. However, adding tank mates increases the demand for space.

If you want to keep a “community” of large fish, you must increase your tank size accordingly. More fish means more waste and more territorial disputes.

Good Tank Mates for Bichirs

Look for medium-to-large fish that occupy the upper levels of the tank. Good choices include:

• Silver Dollars (Great dither fish)
• Severum Cichlids (Peaceful giants)
• Large Datnoids (Compatible predators)
• Giant Gouramis (Top-level dwellers)

Avoid small fish like Neons or Guppies. To a bichir, these are not friends—they are expensive snacks!

Space for Multiple Bichirs

You can keep multiple bichirs together, as they are quite social for predators. They often “pile” on top of each other in a behavior called a “bichir stack.”

If keeping a group, ensure there are plenty of hiding spots. Large pieces of driftwood and PVC pipes make excellent caves.

For a group of three Senegals, a 75-gallon tank provides enough floor space for everyone to have a “home base.”

Frequently Asked Questions (FAQ)

Can a Senegal Bichir live in a 20-gallon tank?

Only as a very young juvenile. They will quickly outgrow a 20-gallon tank within a few months. A 40-gallon breeder is the minimum long-term home.

Do bichirs need a long or tall tank?

Always choose a long and wide tank. Height is the least important dimension for a bichir, as they spend 90% of their time on the substrate.

What happens if my bichir jumps out?

If you find them quickly, put them back in the tank immediately. They can breathe air and may survive being out of water for several hours if they stay moist.

How often should I change the water in a large bichir tank?

I recommend a 25–30% water change every week. Because they eat high-protein food, nitrates can build up quickly, even in large tanks.

Can I keep a bichir with goldfish?

No, I would not recommend it. Goldfish prefer cooler water, while bichirs are tropical fish that need temperatures between 75°F and 82°F.

Conclusion

Choosing the correct bichir fish tank size is the most important responsibility you have as a keeper. These fish are hardy, but they require the dignity of space to live out their long lives.

Remember to prioritize the footprint, invest in a heavy lid, and choose a species that fits your long-term budget and space. Whether you choose a small Senegal or a massive Endlicheri, you are in for a rewarding experience.

Don’t be intimidated by the large tank requirements! There is nothing quite like the prehistoric elegance of a bichir patrolling its territory.

Happy fish keeping, and enjoy your journey with these incredible living fossils! Your Aquifarm community is always here to help you succeed.