55 Gallon Hexagon Aquarium – A Complete Guide To Setup, Stocking

Finding the perfect centerpiece for your living room can be a challenge, but few things capture the eye quite like a 55 gallon hexagon aquarium. While standard rectangular tanks are the norm, the unique vertical profile of a hexagon offers a 360-degree view that transforms any corner into a living piece of art.

Setting up a tall, six-sided tank comes with its own set of rewards and hurdles. If you are worried about whether you can maintain a tank this deep, don’t worry—this setup is perfect for beginners and intermediate keepers alike once you understand the mechanics of vertical water columns. In this guide, I will walk you through everything from equipment selection to stocking the best fish for this specific shape.

We will cover how to manage dissolved oxygen levels, choose the right plants, and ensure your fish have the swimming space they need. By the end of this article, you will have a clear blueprint for creating a thriving, healthy aquatic ecosystem in your 55 gallon hexagon aquarium.

The Unique Appeal of the 55 Gallon Hexagon Aquarium

The first thing you notice about a hexagon tank is its footprint. Unlike a standard 55-gallon “long” tank, which stretches four feet across, the hexagon version stacks its volume vertically. This makes it an ideal choice for hobbyists with limited wall space who still want a high-capacity system.

However, the 55 gallon hexagon aquarium presents a smaller gas exchange surface area compared to its rectangular cousins. In the aquarium world, the surface of the water is where carbon dioxide leaves and oxygen enters. Because a hexagon is narrower, we have to be more intentional about water movement to keep the environment healthy.

Another factor to consider is the hexagonal aquarium stand. Because of the unique shape, you cannot simply use a standard cabinet. You need a stand specifically designed to support the weight of nearly 500 pounds of water, substrate, and glass, distributed across a six-sided base. Stability is the name of the game here.

Understanding Water Pressure and Glass Thickness

Because these tanks are taller, the water pressure at the bottom is significantly higher than in a shallow tank. Most manufacturers use thicker tempered glass for a 55 gallon hexagon aquarium to compensate for this. When you are cleaning the tank, always be mindful of the seals at the six corners, as these are the primary structural points.

If you are still deciding if this is the right size for you, it helps to look at choosing the right hexagon dimensions to see how the height fits your intended space. A 55-gallon model is usually the “sweet spot” where you have enough volume for stability but a manageable height for maintenance.

Technical Challenges: Depth and Oxygenation

The most significant hurdle with a tall tank is vertical thermal stratification. This is a fancy way of saying that the water at the top might be much warmer than the water at the bottom. Since heat rises, a poorly circulated tank can develop “dead zones” where the water is stagnant and cold.

To combat this, you need a high-quality submersible heater. Instead of placing it horizontally at the top, I recommend placing it at a 45-degree angle in the lower third of the tank. This ensures that as the water heats up, it creates a natural convection current, pulling cooler water down and pushing warm water up.

Maintaining Dissolved Oxygen Levels

As mentioned, the limited surface area can lead to lower dissolved oxygen levels if you aren’t careful. To solve this, I always suggest adding an air stone or using a filter with a spray bar. Breaking the surface tension is the most effective way to ensure your fish can breathe easily, especially during the night when plants consume oxygen instead of producing it.

You can also use a powerful canister filter to drive circulation. By positioning the intake near the bottom and the output near the top, you force the entire water column to move, preventing the stratification we mentioned earlier. This is a critical step for a successful 55 gallon hexagon aquarium.

Choosing the Right Equipment for Depth

When you are shopping for gear, “standard” often won’t cut it. You need tools that can reach the bottom and lights that can pierce through 24 to 30 inches of water. If your equipment isn’t up to the task, you’ll find yourself struggling with algae at the top and dying plants at the bottom.

Lighting and PAR Value Depth Penetration

For a planted 55 gallon hexagon aquarium, the PAR value depth penetration is your biggest concern. PAR (Photosynthetically Active Radiation) measures the light energy available for your plants. Most budget LED strips lose their intensity halfway down a tall tank.

Look for high-intensity LED fixtures or “pendant” style lights that can be focused downward. If you want to grow lush greens at the substrate level, you need a light capable of reaching the bottom with enough energy to trigger photosynthesis. Without this, your ground cover plants will “stretch” toward the surface and eventually wither.

Filtration Strategies

While a hang-on-back (HOB) filter can work, a canister filter is vastly superior for this tank shape. It allows you to hide the bulky equipment inside the stand, keeping the focus on the beautiful 360-degree view. More importantly, you can customize the length of the intake pipes to reach the very bottom of the tank.

When selecting your model, it is helpful to browse the top-rated filters for 55-gallon systems to ensure you have enough GPH (gallons per hour) to cycle the water effectively. Aim for a turnover rate of at least 5 to 7 times the tank volume per hour.

Aquascaping the Vertical Column

The beauty of a 55 gallon hexagon aquarium is the height, so don’t be afraid to use it! Instead of a flat landscape, think about “layering” your decor. You want to create a central pillar or a sloping mountain of rock and wood that draws the eye upward.

Large pieces of driftwood, like Spider Wood or Manzanita, are perfect for this. They have long, reaching branches that provide “perches” for fish at different levels of the tank. This also creates natural territories, which can reduce aggression among your aquatic residents.

Best Plants for Tall Tanks

You need plants that can grow tall without becoming “leggy.” Here are a few expert favorites for a 55 gallon hexagon aquarium:

• Echinodorus grisebachii (Amazon Sword): These are the kings of the tall tank. They grow massive, broad leaves that fill the middle and upper sections of the water column.
• Vallisneria americana (Jungle Val): This plant produces long, ribbon-like leaves that will reach the surface and trail across the top, creating a beautiful “curtain” effect.
• Anubias on Driftwood: Since Anubias doesn’t need to be buried in the substrate, you can zip-tie it to branches halfway up your hardscape to fill empty vertical space.

Remember that deeper water means less light reaches the bottom. If you aren’t using high-end lighting, stick to low-light plants like Cryptocoryne or Java Fern for the substrate level.

Stocking Ideas: Who Thrives in a Hexagon?

Not every fish is suited for a 55 gallon hexagon aquarium. High-energy swimmers like Giant Danios or Rainbowfish prefer long, horizontal stretches to sprint. In a hexagon, you want fish that appreciate vertical room or those that are “stately” swimmers.

The Majestic Pterophyllum scalare

The Angelfish (Pterophyllum scalare) is arguably the best fish for this tank. Their tall, thin bodies are perfectly evolved for navigating through vertical plants and wood. A pair of Angelfish will happily claim the middle of the tank as their kingdom, providing a stunning focal point.

Top and Bottom Dwellers

To make the tank look full, you need to stock for every level. For the bottom, a group of Corydoras or a Bristlenose Pleco will keep the substrate clean. For the top, consider Hatchetfish or a large school of Marbled Gouramis. They will hang out near the surface, taking advantage of the gas exchange surface area.

If you are looking for more variety, check out this guide on compatible fish for 55-gallon tanks. Just remember to avoid “active” swimmers that need length more than height.

Unique Value: The Hexagon Tank Maintenance Checklist

Maintaining a tall tank requires a slightly different approach than a standard one. Use this checklist to stay on top of your 55 gallon hexagon aquarium care:

| Task | Frequency | Expert Tip | | :— | :— | :— | | Water Testing | Weekly | Check for nitrate spikes; hexagons can have “dead zones” where waste accumulates. | | Glass Scrubbing | Weekly | Use a long-handled scraper. Magnetic cleaners can be tricky on the angled corners. | | Substrate Vacuuming | Bi-Weekly | Ensure you reach the center of the tank where debris often settles. | | Filter Maintenance | Monthly | Clean your canister media in old tank water to preserve beneficial bacteria. | | Pruning Plants | Monthly | Trim Vallisneria americana if it begins to block too much light from the surface. | | Heater Check | Daily | Ensure the submersible heater is functioning to prevent thermal layering. |

Common Pitfalls and How to Avoid Them

One of the biggest mistakes I see beginners make with a 55 gallon hexagon aquarium is overstocking the bottom. Because the floor space is smaller than a standard tank, you cannot keep as many bottom-dwelling species. If you put too many Cories or loaches down there, they will constantly bump into each other, leading to stress and disease.

Another issue is “The Reach.” Unless you have very long arms, reaching the bottom of a 30-inch deep tank is difficult. Pro tip: Keep a pair of extra-long aquascaping tweezers and scissors handy. You will thank me the first time a plant floats up and you don’t have to soak your entire shoulder to stick it back in!

Lastly, don’t ignore the importance of aquarium heater watts per gallon. Because tall tanks lose heat differently, you want a heater that is slightly “overpowered” for the volume to ensure it can maintain a steady temperature throughout the vertical column.

Frequently Asked Questions

Is a 55 gallon hexagon aquarium hard to clean?

It can be more challenging due to the depth. You will need a long-handled gravel vacuum and a tall step stool to reach the back corners. However, with the right tools, it is no more time-consuming than a standard tank.

Can I keep Goldfish in a 55 gallon hexagon?

I generally don’t recommend it. Goldfish produce a lot of waste and require high oxygen levels. The limited surface area of a hexagon makes it harder to keep the water oxygenated enough for them, and they prefer horizontal swimming space.

How much substrate do I need?

Because the footprint is smaller, you actually need less gravel or soil than a 4-foot tank. Usually, 40 to 50 pounds of substrate will give you a solid 2-3 inch base for your plants.

Do I need two heaters for a tall tank?

While one powerful submersible heater is usually enough, some hobbyists prefer using two smaller heaters—one near the intake and one near the output—to ensure perfectly even heat distribution.

Conclusion

The 55 gallon hexagon aquarium is a rewarding challenge for any fish keeper. It forces you to think differently about space, light, and water flow, but the result is a breathtaking vertical display that you simply can’t get with a standard tank. By focusing on high-quality filtration, powerful lighting, and choosing fish like Pterophyllum scalare that love the height, you will create a thriving underwater world.

Don’t let the depth intimidate you! With a little planning and the right tools, your hexagon tank will become the crown jewel of your home. Ready to start your journey? Take it one step at a time, keep an eye on your dissolved oxygen levels, and enjoy the unique perspective that only a six-sided aquarium can provide. Happy fish keeping!