A Complete Guide to Nano Tanks: Placement and Fish Care

Over the years, I have kept nano tanks of various sizes, from a tiny 0.25-gallon setup to the 20-gallon maximum that is widely considered the upper limit for a nano aquarium.

Through my experiences, I have compiled some important questions to ask yourself before you decide to get one.

Where Will You Put Your Nano Tank?

Before buying a nano tank, it is crucial to decide on its location.

You need a clear idea of where it will go to ensure it fits the space and, more importantly, that the furniture can support it.

Can Your Furniture Support the Weight?

Water weighs approximately 8 pounds per gallon, so a 5-gallon tank weighs around 40 pounds before including any decorations.

I use a general rule of 10 pounds per gallon to estimate the total weight of a filled aquarium.

Following my guideline, a 20-gallon tank could weigh nearly 200 pounds.

When I shop for furniture online, I prefer using Wayfair because most of its product listings include weight capacity information.

Whenever I acquire a new piece of furniture, I always consider if it could safely hold an aquarium.

Even a small tank requires confirming that the desk or stand it sits on can handle the additional weight.

Is the Tank at an Enjoyable Viewing Level?

Another important factor is the tank’s placement.

Is it positioned at a level where you can sit comfortably and enjoy the view?

In most situations, you will be sitting down, not standing, to admire your aquarium.

I have made a few mistakes with placement over the years, especially when I first set up my nano tank area.

When you first get shelving racks, the urge to stack them and fit as many nano tanks as possible is strong.

It can become a bit of an obsession, a fact I now understand from experience. However, I learned the hard way that I do not enjoy aquariums placed on the floor.

They are difficult to appreciate from a standing or seated position, and getting up and down from the floor is not easy for me.

Sitting on the ground to enjoy my tanks is simply not a pleasant experience.

Even some of the lower tanks in my current collection are at a height that I find challenging.

So, think carefully about whether you will be able to sit and truly enjoy your aquarium.

Is it near a couch? Is it placed somewhere you usually spend time?

The position genuinely matters if you want to get the most enjoyment from the experience.

Is the Tank in a Room You Frequently Use?

An additional consideration is the room itself.

Is the aquarium located in a space where you spend a lot of time?

If you are not someone who enjoys going into the basement, and the tank is set up down there, it may end up being neglected.

You might not enjoy it as much simply because you are not around it often.

My favorite aquariums are the ones I have placed in my workspace.

I spend time with my betta fish, Bob, every single day.

We share the workday, which makes the experience more rewarding.

I also have two aquariums in the kitchen, and I see them constantly.

One of my kitchen aquariums is a 15-gallon column model.

While a column-style tank may not be ideal for every type of fish, I find it works well in certain settings.

I keep it in the kitchen and believe its height is perfect.

I can see it clearly whether I am sitting in the dining room or standing in the kitchen.

Almost everyone in my house ends up in the kitchen at some point, so it has become a great location for an aquarium.

The size feels just right, and its placement makes it easy for everyone to enjoy throughout the day.

How Easy Is the Tank to Maintain?

It is important to think about upkeep before buying a nano tank.

While it may seem obvious that every aquarium requires care, the real question is how easy your specific setup will be to maintain.

In most cases, you will be changing the water once a week.

I must mention the 15-gallon column tank again because, in my experience, it is one of the most difficult aquariums to maintain.

Even with long arms, reaching the bottom is still a challenge.

If I need to remove a dead fish, reach into tight spaces around rocks and wood, or reattach a plant, the task becomes frustrating.

In contrast, a standard 10-gallon or 20-gallon tank placed on a desk is much easier to manage.

Accessing the bottom is simpler, which makes routine maintenance far less stressful.

Before making a choice, ask yourself if you can easily reach the bottom of the aquarium.

Maintenance should not feel like a burden if you want to truly enjoy the hobby.

How Will Tank Size Affect Your Aquarium?

The effect of size might seem obvious, but the smaller the aquarium, the faster its water parameters can shift.

Smaller tanks also become dirty more quickly and offer fewer stocking options.

I own several small aquariums, but I choose them with the knowledge that they are very limited in terms of what I can keep in them.

I have some 3-gallon bookshelf tanks and have also used 2.5-gallon tanks in the past.

While a 2.5-gallon tank is often considered the minimum size for a betta fish—and you can indeed keep one in that volume—my experience has changed my perspective on the recommendation.

The more time I spend with fish, especially bettas, the more I realize that while it is technically acceptable, the environment can be uninteresting for both the fish and for me.

There is only a small amount of space for the fish to swim, and watching it move back and forth within a narrow area quickly becomes dull.

Larger aquariums create a completely different experience.

There is more activity, more natural interaction with the environment, and more flexibility if I ever want to introduce different fish.

In very small setups, like 1-gallon aquariums, I do not recommend keeping a betta at all.

Aquariums of that size are better suited for shrimp, snails, or similar small species.

I once owned a 0.25-gallon tank, which was extremely small.

I found it charming, partly because I enjoy miniature setups more than most people probably do.

The 2.5-gallon tank especially appealed to me because it looked like a miniature version of a 20-gallon tank.

It was adorable.

But do I still keep such small aquariums?

No, I do not.

My husband, Jason, supported me as I explored them and worked through their limitations.

Eventually, I moved on to larger tanks.

With the 0.25-gallon tank, the only suitable creatures I could keep were Micro Thai crabs.

They were incredibly tiny and very cute, but the aquarium did not offer many other options.

At most, I could add a shrimp or two.

However, water parameters in a tank of that volume fluctuate dramatically, which makes it a tough environment for almost anything to thrive.

Do You Want to See the Filter and Heater?

When I shop for a new nano tank, I ask myself a simple question: do I want the filter and heater to be visible?

Many all-in-one tanks come with built-in filtration and other equipment hidden behind panels, which can make a big difference in the aquarium’s overall appearance.

In my upstairs studio, I have four tanks from Lifeguard Aquatics.

They are well-designed, with all the filtration concealed.

I find that aquariums with hidden equipment maintain a cleaner, more streamlined look over time compared to setups where I add components myself, such as a sponge filter or a hang-on-back filter on a standard bookshelf tank.

When equipment is placed directly inside the main compartment, the space starts to feel more crowded.

As someone who enjoys aquascaping, I have learned that visible equipment can interfere with the overall layout and design I envision.

A sponge filter or a hang-on-back filter placed in the middle or off to the side can disrupt the balance of the aquascape.

You might not mind that at all, which is perfectly fine, but I have found it helpful to consider how visible equipment might affect both the appearance and the function of my aquarium.

How Will You Clean the Tank’s Crevices?

Before I buy a nano tank, I pay close attention to its crevices.

Every part of the aquarium needs to be cleaned, and small gaps tend to collect algae, detritus, and other debris that I would rather avoid.

I always plan to clean the glass, the sides, and the back. Any crevice can accumulate hard water stains or dried plant matter like duckweed.

For example, I have used 3-gallon bookshelf tanks.

They have a seamless look and lack the usual black silicone lines, which I appreciate.

However, they require a clip-on light unless I use a lighting option that sits behind the aquarium and extends over it—a solution I actually recommend.

When I use a clip-on light, the part that extends into the tank often attracts buildup. I have to remove the light regularly and clean it thoroughly.

The sides and corners of the aquarium can also be difficult to maintain.

Even with a plastic razor blade, I cannot always reach deep into the crevices.

Rounded corners require extra care because scratching the surface is a real risk.

I have learned to think ahead and ask myself how I will clean every part of the aquarium, including the tight corners and edges, before committing to a setup.

What Fish Do You Plan to Keep?

It might seem obvious, but before I buy a nano tank, I always do my research.

I start by asking myself what kind of fish I plan to keep.

If I am getting an aquarium for a betta, then I need to understand the specific behaviors, needs, and tendencies of that species.

For instance, a tank suitable for a betta may be completely different from one intended for a school of green neon tetras.

I keep a 20-gallon long tank for my group of green neons because they are active swimmers.

They move in groups, swimming back and forth across the aquarium, and need enough horizontal space to support that behavior.

I would not place them in a small cube tank, as it would not suit their activity level.

They need room to move and explore.

A betta, on the other hand, has very different needs.

Bettas use a labyrinth organ to breathe air from the surface and travel to the top often.

Because of this behavior, I avoid keeping a betta in a tall aquarium.

I want to ensure the fish stays close to the surface and has easy access to air.

Vertical space is still important, but it should support the betta’s natural behavior, not restrict it.

When I design the aquascape, I also make sure to provide plenty of cover for the betta to feel secure.

No matter what fish I choose, I always research its specific needs before setting up the aquarium.

That way, I can create an environment where the fish can thrive, and I can enjoy caring for it.

Will Your Dream Aquascape Actually Fit?

Many of the insights I offer stem from my own mistakes.

I am sharing my experiences, which include both failures and a few successes—although I admit there have been more failures.

One important consideration is whether I am getting a nano tank because I have a specific aquascape in mind.

Perhaps I already have the driftwood, the plants, and a mental image—or even a saved reference—that inspires the layout I want to create.

If that is the situation, I make sure everything will actually fit inside the aquarium I choose.

I have made the mistake of guessing measurements before, and it did not work out.

The driftwood I planned to use simply could not fit.

This challenge becomes even more pronounced with all-in-one nano tanks.

While they are beautifully designed, many come with fixed lighting elements that limit the available space.

If the wood or hardscape cannot fit beneath or around the light, I am forced to change my entire plan.

Discovering a misfit can be incredibly frustrating, especially if I have to replace the hardscape or reimagine the aquascape from scratch.

I have found a helpful strategy when choosing an aquarium to match existing materials.

If I already have a piece of driftwood and am heading to the store to buy a tank, I bring the driftwood with me.

If I am buying both at the same time, I look around the store for display tanks in similar sizes.

I will either carry the driftwood with me or test its fit in a display tank to see if the dimensions work.

I always bring a measuring tape—it is one of my most useful tools as an aquascaper.

Conclusion

Before selecting a nano tank, I ask myself several essential questions.

First, where will I place the aquarium, and can the furniture safely support its weight?

Water weighs about 8 pounds per gallon, so a filled 20-gallon tank can weigh nearly 200 pounds.

I also consider if the aquarium is positioned at a comfortable height where I can sit and truly enjoy it.

It is also important for the tank to be in a room I use often enough to prevent it from being neglected.

I also think about how easy weekly maintenance will be—can I reach the bottom and clean tight spaces without strain?

Will visible equipment like the filter or heater interfere with the aquascape I have in mind, or would an aquarium with hidden components better support my design?

I consider how quickly water parameters might change in the chosen tank size and whether that matches the needs of the fish I plan to keep.

For example, green neon tetras need horizontal space for schooling, while a betta requires easy access to the surface and plenty of cover.

Finally, if I already have driftwood or hardscape in mind, I measure carefully or test the materials in a similar-sized tank to ensure everything will fit the way I envision it before making a purchase.