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

Setting up a new tank is always an adventure, but choosing a unique shape like a hexagon brings a special kind of excitement to the hobby. If you are looking at a 45 gallon hexagon aquarium, you already know that this isn’t your average “four-walled” glass box.

It is a striking focal point that offers a 360-degree view of your aquatic world, making it a favorite for those who want a blend of art and nature. In this guide, we will walk through everything you need to know to master this vertical environment, from choosing the right gear to selecting fish that actually enjoy the height.

Don’t worry—this setup is perfect for beginners and intermediate keepers alike! By the end of this article, you will have a clear blueprint for success, ensuring your fish stay healthy and your plants grow lush in this unique vertical space.

Why the 45 Gallon Hexagon Aquarium is a Unique Choice

When we think of standard tanks, we usually think of horizontal length, but the 45 gallon hexagon aquarium flips that logic on its head. This tank is all about height and “columnar” space, which offers a completely different aesthetic for your living room or office.

One of the most significant factors to consider is the surface area to volume ratio. In a standard rectangular tank, the large surface area allows for easy gas exchange, but in a hexagon, the surface is narrower.

This means we have to be a bit more intentional about how we move the water and stock the tank. However, the trade-off is a much smaller footprint, allowing you to have a large-volume tank in a corner where a long tank simply wouldn’t fit.

The Aesthetic Appeal of 360-Degree Viewing

Because there are six sides, you aren’t limited to just one “front” view. This allows for island-style aquascaping where the center is the focal point.

You can walk around the tank and see different behaviors from your fish that you might miss in a traditional setup. It creates a “living pillar” effect that is hard to replicate with any other shape.

Space-Saving Footprint

A 45-gallon rectangular tank can be four feet long, requiring a massive amount of wall space. A hexagon tank of the same volume usually takes up less than half that horizontal room.

This makes it an ideal choice for apartments or smaller rooms. You get the benefits of a high-water volume—which provides more stability for your water parameters—without sacrificing your floor plan.

Essential Equipment for Your Hexagon Setup

Setting up a tall tank requires a slightly different approach to equipment than a shallow one. You need to ensure that heat and oxygen reach the very bottom of the vertical swimming space.

Choosing the right hardware from the start will save you from “dead zones” where water becomes stagnant or cold. Let’s break down the must-have gear for this specific shape.

Choosing the Right Hexagonal Aquarium Stand

Safety first: you cannot place a hexagon tank on a standard rectangular stand. The weight distribution is entirely different, and the corners must be properly supported to prevent the glass from stressing.

Always look for a dedicated hexagonal aquarium stand that matches the footprint of your tank exactly. Most manufacturers sell these as combos, and it is highly recommended to go that route for peace of mind.

Filtration Strategies: Reaching the Bottom

Because the tank is deep, standard hang-on-back filters might struggle to pull water from the lower levels. I almost always recommend canister filtration for a tank of this height.

A canister filter allows you to position the intake tube near the substrate and the output near the surface. This creates a vertical loop of water movement that ensures nutrients and heat are distributed evenly.

Heating a Tall Water Column

Heat naturally rises, so in a tall tank, the bottom can sometimes be several degrees cooler than the top. To combat this, use a high-quality submersible aquarium heater.

I recommend placing the heater horizontally near the bottom or at a 45-degree angle near the filter intake. This way, the moving water carries the heat upward throughout the entire column. If you are unsure about the power you need, check out this guide on choosing the right heater wattage for your specific volume.

Aquascaping for Vertical Impact

Aquascaping a 45 gallon hexagon aquarium is a fun challenge because you have so much height to play with. Traditional “foreground, midground, background” rules still apply, but you have to think vertically.

Instead of a slope from back to front, think about building a central pillar or using tall, reaching elements that draw the eye upward. This is where your creativity can truly shine.

Using Tall Aquatic Plants

You want plants that will grow toward the light and fill the upper third of the tank. My personal favorite for this is Vallisneria americana (Jungle Val).

These plants produce long, ribbon-like leaves that will eventually flow across the surface, providing shade and a natural feel. Another great choice is Echinodorus grisebachii (Amazon Sword), which grows wide and tall, acting as a perfect center-piece.

Hardscape Selection: Driftwood and Rocks

In a hexagon, a single, tall piece of spider wood or driftwood can look incredible. Look for pieces that have “branches” reaching toward the surface.

You can zip-tie or glue epiphytes like Anubias or Java Fern to the upper branches of the wood. This ensures that even the middle and upper levels of the tank have lush greenery, rather than just having a “floor” of plants.

Substrate and Depth

Because the tank is deep, light has a harder time reaching the bottom. If you plan on having a carpet of plants, you will need very strong lights or a nutrient-rich substrate to help them along.

For a deeper dive into how to arrange these elements effectively, you might find some inspiration in our guide on foundational aquascaping tips, which can be scaled up for larger displays.

Best Fish Species for a 45 Gallon Hexagon Aquarium

Not all fish enjoy a tall tank. Fish that are “horizontal sprinters,” like Giant Danios or some Rainbowfish, might feel cramped because they can’t swim long distances in a straight line.

Instead, we want to look for fish that appreciate vertical swimming space or those that are more sedentary and “stately” in their movements. Here are some of the best candidates for this setup.

The King of the Hex: Angelfish

Pterophyllum scalare, or the common Angelfish, is arguably the best fish for a 45-gallon hexagon. Their tall, thin bodies are designed for navigating through vertical plants and structures.

A pair of Angelfish will utilize the entire height of the tank. They are majestic, have tons of personality, and they turn the aquarium into a true centerpiece.

Gouramis and Top-Dwellers

Gouramis are labyrinth fish, meaning they breathe air from the surface. In a tall tank, they enjoy hanging out in the upper reaches.

The Trichopodus leerii (Pearl Gourami) is a stunning addition. They are peaceful, hardy, and their intricate patterns look beautiful under aquarium lighting. They fill that upper-middle gap perfectly.

Schooling Fish for the Mid-Water

For your schooling fish, look for “deep-bodied” tetras. Species like Rummy Nose Tetras or Diamond Tetras tend to stay in a tighter group and move gracefully up and down the water column.

Avoid fish that are too small, like Neon Tetras, if you are keeping Angelfish, as they might eventually become a snack! Stick to medium-sized tetras or rasboras for a harmonious community.

Managing Water Quality and Oxygenation

The biggest technical hurdle with a 45 gallon hexagon aquarium is ensuring enough oxygen gets into the water. Because the surface area is small compared to the total volume, dissolved oxygen levels can sometimes dip if the water is stagnant.

Keeping your water crystal clear and well-oxygenated is the secret to a long-lasting, healthy tank. Here is how to manage the unique physics of a hexagon.

Increasing Surface Agitation

The easiest way to boost oxygen is to break the surface tension of the water. You can do this by positioning your filter outlet so it creates ripples across the top.

If you notice your fish hanging out near the surface and “gasping,” it’s a sign that you need more air. Adding a small air stone hidden behind your hardscape can provide that extra boost without ruining the look of your aquascape.

Deep Siphoning Techniques

When you perform water changes, you need a gravel vacuum with a long enough hose to reach the bottom of the 24-to-30-inch depth. It can be a bit of a reach!

Make sure you are getting deep into the substrate to remove trapped waste. Because there is less “floor” space, waste can build up quickly in a small area, so regular maintenance is crucial.

Water Parameter Stability

With 45 gallons of water, you have a good “buffer” against sudden changes in chemistry. However, because the tank is vertical, you should test water from both the top and the bottom occasionally to ensure your circulation is doing its job.

If you need to understand the dimensions better before buying, check out our resource on hexagon tank dimensions to ensure it fits your space perfectly.

Stocking and Compatibility Table

To help you plan your community, I’ve put together a quick compatibility and stocking guide specifically for the dimensions of a 45-gallon hexagon.

| Fish Species | Role in Tank | Quantity | Why they fit | | :— | :— | :— | :— | | Angelfish | Centerpiece | 2 (Pair) | Their tall bodies thrive in vertical space. | | Pearl Gourami | Mid/Top Dweller | 1-2 | Peaceful and enjoys the upper water column. | | Rummy Nose Tetra | Schooling | 8-10 | Tight schoolers that move beautifully together. | | Corydoras Catfish | Bottom Dweller | 6 | Keeps the substrate clean; very active. | | Bristlenose Pleco | Algae Eater | 1 | Stays small and cleans the glass/wood. |

Pro Tip: Always introduce fish slowly. Start with the hardiest species (like the Tetras or Corydoras) to help the nitrogen cycle stabilize before adding the more sensitive Angelfish.

Frequently Asked Questions

Is a 45 gallon hexagon aquarium hard to clean?

It can be slightly more challenging than a standard tank because of the depth. You will likely need a long-handled algae scraper and a long gravel vacuum. However, once you have the right tools, it isn’t much more work than any other 45-gallon setup.

What kind of lighting do I need for a tall tank?

Depth is the enemy of light. If you want to grow live plants at the bottom, you need a powerful LED light with good “PAR” (Photosynthetically Active Radiation) values that can penetrate 24+ inches of water. Look for lights specifically rated for “deep” tanks.

Can I keep a goldfish in a 45 gallon hexagon?

While 45 gallons is enough volume for one or two fancy goldfish, the hexagon shape isn’t ideal for them. Goldfish are high-waste producers and need a lot of surface area for oxygen. A rectangular tank is generally a better fit for their swimming style and oxygen needs.

How do I prevent “dead spots” in the water?

Dead spots occur where water doesn’t circulate. In a hexagon, this usually happens at the very bottom corners. Using a canister filter with a spray bar or adding a small circulation pump (powerhead) near the bottom can keep the water moving effectively.

Can I use a regular rectangular lid?

No, you will need a specific 6-sided lid. Most 45 gallon hexagon aquarium kits come with a fitted hood. If yours didn’t, you may need to have a piece of glass or acrylic custom-cut to fit the rim.

Final Thoughts on the 45 Gallon Hexagon Aquarium

Owning a 45 gallon hexagon aquarium is a rewarding experience that allows you to view the hobby from a different angle—literally! While it requires a bit more thought regarding circulation and lighting, the visual payoff is second to none.

By focusing on vertical elements like Vallisneria and choosing fish like Angelfish that appreciate the vertical swimming space, you can create a thriving, balanced ecosystem. Remember to prioritize canister filtration to keep that deep water moving and always use a proper hexagonal aquarium stand for safety.

Whether you are a beginner looking for your first “big” tank or an experienced keeper wanting a new challenge, the 45-gallon hexagon is a fantastic choice. It’s a conversation starter, a piece of art, and a beautiful home for your aquatic friends. Happy fish keeping!