27 Gallon Hexagon Aquarium – The Ultimate Guide To A Stunning Vertical

Setting up a new fish tank is always an adventure, but choosing a unique shape adds a whole new layer of excitement. If you are looking for a show-stopping centerpiece that doesn’t take up an entire wall, the 27 gallon hexagon aquarium is an incredible choice.

I know what you might be thinking: “Is a tall tank harder to maintain than a long one?” It is a fair question, and the truth is that while they have some unique quirks, they offer a visual depth that standard rectangles simply cannot match. In this guide, I will share everything I have learned about mastering this specific footprint so you can skip the trial-and-error phase.

We are going to cover everything from the best equipment and aquascaping strategies to the specific fish species that thrive in a vertical environment. By the end of this article, you will have a clear, actionable plan to turn your 27 gallon hexagon aquarium into a thriving aquatic masterpiece.

Why Choose a 27 Gallon Hexagon Aquarium?

The first thing most hobbyists notice about a hexagon tank is its “wow factor.” Unlike traditional tanks, the six-sided design provides 360-degree viewing angles, making it a perfect choice for a corner or a spot where it can be seen from multiple sides of a room.

One of the biggest practical advantages is the footprint. Because these tanks are taller than they are wide, they are ideal for apartments or smaller homes where floor space is at a premium. You get the water volume of a mid-sized tank while only using the floor space of a much smaller one.

Before you commit, it is helpful to understand the physical space you’ll need. Checking the hexagon aquarium dimensions beforehand ensures your stand and location are perfectly suited for the weight and height of the setup.

The Aesthetic Appeal of Verticality

In a standard tank, we often think in terms of “left to right” movement. In a 27 gallon hexagon aquarium, we get to think about “top to bottom.” This allows for some truly creative decorating, like using tall pieces of driftwood that reach toward the surface.

This verticality also allows you to see distinct layers of fish activity. You can have bottom-dwellers, mid-water schoolers, and surface-dwellers all occupying their own “floors” of the aquarium, creating a very busy and interesting ecosystem.

Understanding the Unique Challenges of Hexagonal Tanks

While I love the look of these tanks, I have to be honest: they do come with a few technical challenges that you need to prepare for. The most significant factor is the surface area. Because the tank is narrow, there is less surface area for gas exchange compared to a 29-gallon “long” tank.

This means that dissolved oxygen levels can sometimes be lower if the water is stagnant. To combat this, you’ll want to ensure you have good surface agitation. A simple air stone or a filter that breaks the surface of the water will keep your fish breathing easily.

Light Penetration in Deep Water

Another factor is the depth. A 27 gallon hexagon aquarium is significantly deeper than a standard tank of the same volume. Standard lights that come in a kit might struggle to reach the bottom, which can make growing low-light plants a bit tricky if you don’t upgrade your lighting.

Cleaning can also be a bit more of a “reach.” You might find yourself needing extra-long algae scrapers or planting tweezers to reach the substrate without getting your shoulders wet! It’s a small price to pay for the beauty of the tank, but it’s something to keep in mind.

Essential Equipment for Your 27 Gallon Hexagon Setup

Choosing the right gear is the foundation of a successful tank. Because of the unique shape, you can’t always just grab the first thing you see on the shelf. You need equipment that can handle the depth and the specific flow patterns of a six-sided environment.

Choosing the Right Filter

A reliable Power filter is usually the go-to for this size. Look for one that has an adjustable flow rate. You want enough turnover to keep the water crystal clear, but you don’t want to create a “whirlpool” effect that exhausts your fish in the narrow space.

If you prefer a cleaner look, a small canister filter is also an option. This allows you to hide the intake and output pipes behind your hardscape, keeping the focus entirely on your fish and plants rather than the plastic equipment.

Heating and Temperature Stability

Because these tanks are tall, heat can sometimes layer, with the top being warmer than the bottom. I highly recommend using a high-quality Submersible heater placed near the filter intake. This ensures the warm water is circulated evenly throughout the entire 27 gallons.

When selecting your heater, make sure it has enough power to maintain a steady temperature. You can check a guide on heater wattage requirements to ensure you aren’t under-powering your system, especially if your home gets chilly in the winter.

Lighting and the LED Hood

Most 27 gallon hexagon aquarium setups come with a specialized LED hood. These are great for viewing, but if you plan on keeping live plants, check the PAR (Photosynthetically Active Radiation) values. For a deep tank, you may need a more powerful LED to ensure your ground-cover plants get the energy they need.

Aquascaping Your Vertical Space

This is where the fun really begins! Aquascaping a hexagon tank is different from a rectangle. You want to create a central focal point that draws the eye upward. I like to use a “pillar” approach, where the tallest elements are in the center, tapering down toward the glass.

Hardscape Selection

Look for tall, thin pieces of Manzanita wood or Spider wood. These branchy textures look amazing in a hexagon tank because they provide plenty of perching spots for shrimp and hiding places for fish without blocking the view from any of the six sides.

For rocks, consider stacking flat stones like slate or using vertical “dragon stone” pieces. Just be sure that any tall structures are very stable. I often use aquarium-safe epoxy to “glue” my rocks together so they don’t tip over during a deep cleaning session.

The Best Plants for Tall Tanks

You want plants that naturally grow tall and narrow. My absolute favorite for this setup is Vallisneria spiralis. It grows in long, ribbon-like strands that will reach the surface and then trail across the top, creating a beautiful jungle effect.

Another great choice is the Echinodorus amazonicus, commonly known as the Amazon Sword. It has wide, reaching leaves that fill out the mid-section of the tank perfectly. For the very bottom, stick with hardy options like Anubias or Java Fern attached to your hardscape, as they don’t require high light levels at the substrate.

Best Fish for a 27 Gallon Hexagon Aquarium

Stocking a hexagon tank requires a bit of thought. Because there is less horizontal “swimming room,” you want to avoid high-energy “sprinters” like Giant Danios. Instead, look for fish that are comfortable moving vertically or those that prefer to hover and explore.

Centerpiece Fish Options

A Trichogaster lalius (Dwarf Gourami) is a fantastic centerpiece for this tank. They are colorful, slow-moving, and love to weave through the tall plants. Their labyrinth organ also allows them to breathe air from the surface, making them very hardy in vertical setups.

Many people ask about Pterophyllum scalare (Angelfish). While a 27 gallon hexagon aquarium is tall enough for them, the horizontal space is a bit tight for a pair. If you do keep one, make sure it is a single individual and that the tank is not over-crowded with other large fish.

Schooling and Bottom Dwellers

For the upper layers, Carnegiella strigata (Marbled Hatchetfish) are stunning. They stay right at the surface and have a very unique shape. Just make sure your lid is tight-fitting, as they are legendary jumpers!

At the bottom, a group of Corydoras paleatus (Peppered Cory) will do a great job of cleaning up any leftover food. They are peaceful, social, and fun to watch as they “snuffle” through the sand. If you are interested in invertebrates, you might also consider how many shrimp per gallon you can safely add to help with algae control.

Stocking and Compatibility Table

To help you visualize a balanced community, here is a sample stocking plan for a 27 gallon hexagon aquarium. This focuses on temperament, swimming levels, and space requirements.

Fish Species	Role/Level	Quantity	Benefit
Dwarf Gourami	Centerpiece (Mid)	1	Stunning color and calm personality.
Marbled Hatchetfish	Schooler (Top)	6	Unique shape; occupies the surface.
Neon Tetras	Schooler (Mid)	8-10	Classic brightness and tight schooling.
Peppered Corydoras	Cleaner (Bottom)	6	Keeps the substrate clean and active.
Nerite Snails	Algae Eater (All)	2-3	Excellent at cleaning glass and décor.

Maintenance and Care Tips

Maintaining a 27 gallon hexagon aquarium isn’t necessarily harder, but it requires the right tools. Because the tank is deep, detritus can settle in the corners of the hexagon where water flow might be slightly lower. I recommend using a gravel vacuum with a long attachment to reach those spots during your weekly water changes.

Keep an eye on your algae growth. Since the glass panels are smaller and more numerous, you’ll want to wipe them down regularly to maintain that 360-degree clarity. A magnetic glass cleaner is a lifesaver here, as it allows you to clean the bottom sections without reaching your whole arm into the tank.

Testing and Water Quality

Consistency is key. Because of the lower surface area for oxygen exchange, you should be diligent about testing your parameters. Ammonia and nitrite should always be zero, and I recommend keeping nitrates below 20ppm through regular 25% water changes.

If you notice your fish gasping at the surface, it’s a sign that your dissolved oxygen levels are low. This can happen if the water gets too warm or if the surface is too still. Increasing the flow from your filter or adding a small air pump will fix this issue almost immediately.

Frequently Asked Questions

Is a 27 gallon hexagon aquarium good for beginners?

Yes, it is! While it has some unique needs regarding light and oxygen, it is a manageable size. It is much more stable than a small nano tank but doesn’t require the massive equipment of a 75-gallon setup. Just be sure to choose slow-swimming fish.

Can I use a standard stand for this tank?

No, I strongly recommend using a stand specifically designed for a hexagon footprint. The weight of 27 gallons of water (plus substrate and rocks) is roughly 250-300 pounds. A dedicated stand ensures the weight is distributed evenly across all six corners.

What is the best substrate for this tank?

Since you’ll likely be growing tall plants like Vallisneria spiralis, a nutrient-rich aquarium soil capped with fine gravel or sand is ideal. This gives the roots plenty of “food” while making it easy for your Corydoras to sift through the surface.

How many fish can I put in a 27 gallon hexagon?

Avoid the “inch per gallon” rule here. Because the surface area is smaller, you should stock a bit more lightly than you would in a 27-gallon long tank. A community of about 15-20 small fish (like tetras and cories) plus one centerpiece fish is usually the sweet spot.

Final Thoughts on the 27 Gallon Hexagon Aquarium

The 27 gallon hexagon aquarium is a rewarding choice for any hobbyist who wants to break away from the traditional rectangular look. It challenges you to think vertically with your aquascaping and rewards you with a stunning, multi-dimensional view of your aquatic world.

By focusing on tall plants, ensuring good water circulation for oxygen, and choosing fish that enjoy a vertical environment, you can create a healthy and beautiful ecosystem. It’s a conversation piece that brings a slice of the underwater world into your home in a truly unique way.

Don’t be intimidated by the height—with the right tools and a bit of planning, your hexagon tank will be the envy of everyone who sees it. Happy fish keeping!