Fish Tanks – Long vs Tall vs Cube

When my friends ask me for advice on tank type, I usually tell them to go for a long one. I find that the long ones fit my fish and me the best. They offer more swimming space, the largest surface area for gas exchange (which means more oxygen), and more ground area for plants.

What are the common tank types?

Tanks are divided into three main categories, according to their shape. The standard tanks available on the US market can be long, tall, or cube-shaped. In addition, there are, of course, other custom-made tanks in different shapes. And finally, there are bowls, which, as explained later, are far from ideal for your fish.

Prices do not depend on the tank shape but on the glass quality, tank size, and manufacturer. Custom-made tanks will be more expensive, but standard ones usually don’t vary much.

We will discuss below the three more common tank types:

The long tank

These tanks have a rectangular shape, with their length being larger than their height.

Benefits of long tanks:

• Easier to clean and maintain.
• The filter creates a more gentle and stable water flow.
• More space for swimming and aquascaping.
• A larger water surface area allows for more gas exchange, resulting in more oxygen.
• Easier for live plants to grow, as light can penetrate until the bottom.
• More stable shape, harder to knock down.
• Preferred by most fish species, as they make better use of all the space.

Drawbacks of long tanks:

• Occupy more room in your house.
• More room for debris accumulation.

The tall tank

Also rectangular in shape, but with a larger height than width.

Benefits of tall tanks:

• Less space is occupied in your room.
• More layers for different species.
• Less room for debris accumulation.

Drawbacks of tall tanks:

• Harder to clean as you need to reach deeper.
• Less space for swimming and decorations. This makes it less useful as a community tank.
• Light won’t penetrate until its bottom, making it harder for live plants to thrive.
• The filter cannot circulate water evenly, which may lead to cyclone development.
• Easier to knock down.
• Only preferred by a few species, like angels.

The cube tank

All sides are of equal length, being square-shaped.

Benefits of cube tanks:

• Combines the advantages of a shallow tank with a smaller footprint in your house.
• Easy to clean and maintain.
• Great as a nano tank.
• Allows light penetration, which is good for the plants.
• Very stable.
• Allows a steady water flow.

Drawbacks of cube tanks:

• Limited swimming area and surface for gas exchange.
• Limited dimensions and height, especially for angelfish that like deep tanks.

What about Bowls?

You might see bettas or goldfish in a bowl. They are small, cheap, and look cute, but are far from ideal for your fish. There is no room for heater, filter, and plants. The swimming area is too restricted for a fish to have a healthy, stress-free life. Even with frequent water changes, the water parameters will be unstable.

Gallons

The standard measurement for a fish tank is in gallons.
Most home tanks fit into the following size ranges:

Small tanks from about 2.5 gallons to 15 gallons.
Medium tanks from about 20 gallons to 40 – 45 gallons.
Large tanks from about 50 gallons up to 225 gallons.

Tank weight

Tank weight is often forgotten when thinking about where we might place our tank. The weight of a filled tank is vastly different from that of an empty one.

The aquarium glass, substrate, decorations, plants, filters, heaters, and water add to the final tank weight.

Usually, the substrate weight is 1lb/gallon. Water usually weighs around 8.34 lbs/gallon, but it’s better to calculate 10 lbs/gallon to have a safety buffer. The equipment like filters, pumps, and everything else, has the weight stated on their packaging, so you can easily calculate the extra weight.

Taking all these into account, let’s see how heavy can a long tank get before adding any fish or equipment (we will consider glass tanks here):

10 gallon tanks can reach about 121 lbs (tank – 11 lbs , water – 100 lbs, gravel – 10 lbs).
20 gallon tanks can reach about 245 lbs (tank – 25 lbs, water – 200 lbs, gravel – 20 lbs).
55 gallon tanks can reach about 683 lbs (tank – 78 lbs, water – 550 lbs, gravel – 55 lbs).
75 gallon tanks can reach about 965 lbs (tank – 140 lbs, water – 750 lbs, gravel – 75 lbs).
150 gallon tanks can reach about 1931 lbs (tank – 281 lbs, water – 1500 lbs, gravel – 150 lbs).

Placing your tank

Traditional furniture like drawers is fine for smaller tanks up to 20 gallons. For larger ones, however, more robust furniture is preferred.

Pet stores sell a wide range of aquarium stands designed to hold a lot of weight. Make sure you calculate your aquarium tank weight correctly before purchasing a stand. If you are not sure, go for a larger one.

Special built-in stands are best for large tanks that get close to or over a ton. Depending on your building, floor reinforcement may also be necessary. A structural engineer will be able to advise you about this before bringing your new tank in.

The manufacturer will recommend the best stands to support their tanks.

Pressure

As the footprint is smaller in the case of high tanks, be extra careful when considering pressure. Pressure is weight divided by footprint area, and it is a lot higher in the case of high tanks.

Let’s summarize the tank size considerations.

Only a few aquarium fish species like to swim from the bottom to the top and specifically require a tall tank. Angel fish are a good example. Others won’t care, or will even prefer a wider tank rather than a tall one.

The greatest CO2 exchange takes place at the water surface, so a wider surface means that more oxygen will reach your tank naturally. Most aquarium fish love to have as much oxygen as they can and will swim close to the surface.

A bigger floor area also allows you to place more decorations, plants, wood pieces, or toys for your fish.

Light penetrates until a limited depth of your tank, so taller tanks may not be efficiently lit all the way through the bottom. This also means that if you decide to have natural plants, it may be difficult for them to thrive in low light.

A tall tank will definitely take up less floor/furniture space and will create different layers for your fish to swim without getting into fights. This will also allow you enough room to add more tanks should you become an addict.

Filters will reach longer tanks more evenly, which helps for easier and more effective cleaning, as well as smoother currents.

General maintenance: usually, shallower tanks are a lot easier to clean than deeper ones. This is because it’s easier to reach the tank bottom when you need to vacuum any debris, or pick up dead plants.

Placing your tank

It’s crucial to measure your space correctly, considering several factors. You want your tank to be visible, look pretty, and be a good home for your fish. At the same time, you want to be able to clean it and have easy access to all its features.

Before deciding on what size you want your tank to be, take into account the following factors:
Take good measurements of the area you want to place your tank in, and calculate how much space the stand will take.

Consider letting enough space around it so that you can move around your tank, clean it, check the set-up, and everything else you need to do. You won’t be able to do them while your tank is being squeezed in a cramped space. Allow enough space for external gear like hoses, filters, etc.

It will be very helpful to place the tank near a water hose.

If you already have a piece of furniture you want to place your tank on, find out if it will hold its weight. The manufacturer will be the most indicated to tell you this.

Consider the area you will place your tank in:

• If it is in a busy area, your fish might get stressed.
• The sunlight might be too bright if it is too close to a window.
• Consider whether pets or small children will have access to it.
• If keeping your tank on an upper floor, calculate how much weight the floor can take. Some buildings may have restrictions about the tank size you can keep, as some large tanks filled with water, decorations and everything may even reach up to 1 ton.

Which is the most popular tank type?

With so many advantages like easier maintenance, larger swim area and light penetration, long tanks are definitely the most popular in the aquarium hobby. Their only major drawback is the area occupied in the house.

What are rimless tanks?

Rimless tanks are just that: plain glass or plastic tanks that don’t have visible braces around the edges, or lids whatsoever. They are more aesthetically pleasing, easier to clean and modern overall. They offer a more natural look which don’t distract from the underwater view.

They are great for many calm fish that swim slower and won’t jump out of the water.

Putting a lid

Bettas can jump and snails will crawl on your tank walls. Seriously consider placing a lid over your tank to keep them safely contained.

If you only keep bettas and no snails, an alternative would be filling your tank less, so you will have a higher distance from the water surface to the tank rim. But this will result in you not being able to fully make use of your entire tank volume.

Do betta fish prefer long or tall tanks?

In the wild, bettas live in wide, shallow ponds and puddles with little to no currents. A wider water surface allows more gas exchange between the water and the air, so more surface area means more oxygen is absorbed into the water.

A longer tank will allow you to keep more fish in the same water volume for the same reason. Bettas enjoy the extra swimming space and will take advantage of the whole tank length, swimming back and forth and exploring their surroundings.

Another advantage of a longer tank is that the filter cannot create strong currents. Instead, it creates a slower flow, which is gentler for your bettas.

You can read our betta fish tank size guide here.

Conclusion

There are many things to consider when choosing a tank type, like the kinds of plants you will be using, the light penetration you need, your fish species requirements and more.
A long tank is usually the best choice, but your case may vary.