The Best 2.5 Gallon Fish Tanks of 2021


Aquatic pets make great companions in anybody’s household. Very quiet, they do not disturb you as much as other pets. However, they are not dogs or cats that you could easily leave alone, as they depend on you for food, and cleanliness. Albeit with the right gear — such as tanks, filters, and food — they can be low-maintenance. To thrive and be healthy, these animals need ample space and superior conditions, especially ones that mimic their natural habitats. If you want to keep aquatic friends while conserving space, it would be perfect to start with only the best 2.5 gallon fish tanks!

What is the Best 2.5 Gallon Fish Tank

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Top 6 Best 2.5 Gallon Fish Tanks Reviews

1. Fluval Spec III 2.6 Gallon Aquarium Kit


Fluval’s Spec III 2.6-gallon Aquarium Kit is a compact nano-aquarium great for small spaces. The tank comes with a powerful 31-LED Lamp at the top, to highlight your wonderful friend/s and plants! It is perfect for the small work desks or tabletops of your home because of its elegant look, which is owed to the etched-glass with aluminum trim and honeycomb back cover. All of these make the tank put-together, supporting both its amazing features and stylish design.

The model does not come equipped with a heater, which is something some breeds of fish need. Despite that, the Spec III does not come as a 2.6-gallon tank alone, as it also comes with a powerful 3-stage filtration! The 3-stage filtration system is accompanied by a strong circulation pump with adjustable output. So, you can keep your fish undisturbed by strong currents!


  • Gorgeous minimalistic design
  • Quiet operation
  • Comes with powerful 31-LED Lamp
  • Also comes equipped with 3-stage filtration system
  • Does not take up too much space


  • Does not come with heater

2. Umbra 2 Gallons Mini Aquarium Tank Bowl


The Umbra 2-Gallon Mini Aquarium is a super chic aquarium made specifically for desktops. The modern design is not just made for looks, though, as it allows you as well to stack tanks of the same model on top of each other! Filtration would not be a problem when stacked, as there is a space at the top of the tank where pipes can easily fit through. The plastic outer shell of the actual glass tank is detachable. So, you can freely paint it the way you want it to look.

Although the plastic casing impedes a perfect 360° view of the tank and its insides, it can swiftly be detached to make tank cleaning and maintenance extremely quick. This little tank would be terrific for one single tiny tropical fish (not good for larger fish), yet accessories should be kept to a minimum, to give the fish sufficient space.


  • Beautiful modernized design
  • Stackable with similar tanks
  • Detachable plastic casing for ease of cleaning
  • Customizable
  • Easy maintenance


  • Casing does not allow clear 360° view

3. Koller Products AquaView 2 Gallon 360 Fish Tank


Koller Products’ AquaView 2-Gallon Fish Tank is a fantastic plastic-walled aquarium for your quaint tabletop or desktop! The body of the tank is surrounded by plastic, which gives a somewhat glassy look. Flexible and durable, the material prevents any cracks or breakage from high impacts. With its cylindrical shape, it also approves for a 360° view. Another feature of this cute tank is its multicolored LED Lamp, which you can choose seven colors from, with an additional built-in timer with 2 Hour, 4 Hour, and Always On choices.

While there are reports that the built-in filter does not last longer than two months, it is still the best feature of the tank! The filter was manufactured by Tetra themselves, equipped with Tetra XS replacement cartridges. Even if the filter breaks, you can simply contact the company and they will follow it up with a replacement filter!!


  • Durable and flexible material
  • Cylindrical shape allows 360° view
  • Comes with multicolored LED Lamp with timer
  • Built-in 25 gph internal filter
  • Spacious for single small fish


  • Hard-to-replace built-in filter

4. Aqueon 2.5 Gallon Aquarium Starter Kits with LED Lighting


The Aqueon 2.5-Gallon Aquarium Starter Kit is a compact and multifunctional desktop aquarium. Designed by Aqueon particularly for tight spaces like desktops or dorm rooms, the small aquarium comes in a bow-like shape. In spite of this space-conservative design, Aqueon still managed to incorporate a lighting and filtration system into the machine. You would not need to worry about your electricity bill when it comes to turning the LED light on, as it is claimed to be energy-efficient.

The filter intake tube poses a risk of the fish getting injured, but you can smoothly cover it up with a sponge, or turn it on while you are able to keep watch. Additionally, the top of the tank includes a designated feeding hole, to help you readily feed your fish. To top it all off, Aqueon used their very own QuietFlow Filter for a virtually noiseless operation!


  • Compact and modernized design
  • Comes with LED Lamp and AqueonQuietFlow Filter
  • Designated feeding hole for convenience
  • Quiet operation
  • Spacious enough for a single Betta


  • Filter intake tube may injure fish

5. Koller Products AquaView 2.5 Gallon Fish Tank


Koller Products’ AquaView series has added the 2.5-Gallon Fish Tank particularly for children. The product was manufactured with plastic as its main substance, constructing it to be shatterproof, leakproof, and impact resistant, which causes it to be safe to place around your children. The plastic casing permits viewing from different angles, but this may be distorted at the edges, as it is shaped as a cuboid.

Many purchasers have found that the only problem with the tank is that the filter does not fit into its designated place on the tank lid, but they themselves were able to solve it quickly by carving the lid with the right size. Once you get past this, you will find that the filter with Koller’s own XS cartridges works very silently. Furthermore, the lights are definitely an eye-catching feature, as you can change its colors and set a timer on them.


  • Durable material made especially for children
  • Clear view from various angles
  • Built-in filter and LED Lamp
  • Muted operation
  • Spacious for Betta fish


  • Lid needs to carved to install the filter

6. Koller Products Betta Tank 2 Gallon Hex Fish Bowl


Koller Product’s Hexagonal 2-Gallon Fish Bowl turns an unthinkable shape for fish bowls into a reality. The shape allows the product to support the space it provides for fish and accessories, while seamlessly fitting in any corner of your home. Just like other Koller aquariums, this fish bowl comes produced in plastic, which compels it to be durable, leakproof, and shatterproof. This is an amazing option, especially around children, as it would not break when falling from a relatively high place.

Granting the product is flimsy at first touch, it does become sturdy when filled with water. The fish have enough area to swim around, and at the same time, gives you enough room to place some accessories. The simplicity of this bowl permits you to customize it however you wish to, so do not be afraid to bring out your artistic side!


  • Unique hexagonal shape
  • Clear view from different (not all) angles
  • Spacious for a single betta or goldfish
  • Durable, shatterproof plastic material
  • Customizable


  • Product is flimsy straight out of the package

2.5 Gallon Fish Tanks Buying Guide

Browsing through a menu of 2.5-gallon fish tanks, you could surely be attracted to the eye-catching and top-tier models. Nevertheless, you should always think twice about how these models will belong in your home, room, or desk. Oftentimes, we can just forget to consider certain aspects of our living space when buying fish tanks, so here are three things that you should consider first before adding anything to cart.


This is the most obvious thing you have to recognize. Manufacturers regularly leave a description of what their products can do; there are some with features that others do not have. Seek to remember what you have at home that comes built-in the tank, because you can conveniently save money by using what you already keep, rather than unnecessarily buying another item.

How well does the product work? Take some time to do some research on the product and read reviews online. If purchasing from a local pet store or aquarium, try asking the sales clerk what they think of the product, as they are knowledgeable of pet care.


Space is a factor that fairly a lot of people overlook. There are space-conservative models of fish tanks, but that does not mean that they will suit your desk or room. So that you would not have to worry about the placement of the tank, take some time to size up your area before hitting that “Buy Now” button. Allocate a space precisely for the tank only, as this will aid in making your desk, room, or home more organized.


How long does the product last? Typically, you would not want to buy a product with a very short lifespan, as that is just a waste of money. See whether the materials used are durable enough and can effortlessly be preserved to last you and your fish a long time.


Take some time to ponder how well the tank will match with the other décor in your space. You would not want a “sore thumb” sticking out amongst your decoration, as it could be bothersome. Think whether placing the tank here or there will look natural in your home, and picture how it would look like beside other things.

What is a 2.5 Gallon Fish Tank?


A fish tank is a container where you can shelter pet fish. Categorically, a 2.5-gallon tank is that which is appropriate for most fishes, providing adequate space for growth and swimming around. This grants you enough space to make the tank a stylish and accessorized home for your fish.

Types of 2.5 Gallon Fish Tanks

In the market, there are commonly four types of 2.5-gallon fish tanks, two of which fall under the category “Material”, and the other two under “Functionality”.


The most common type of 2.5-gallon fish tanks are made with glass. Glass exchanges fragility for sophistication, as glass awes viewers. It is a bit more expensive than other materials in the market, but they are most likely to fit in (or even add to) the general aesthetic of your home décor.

People instantly think of glass for fish tanks due to commerciality. Despite its frailty, it is a versatile and trustworthy material, and plenty prefer it over dependable and malleable plastic simply because of its class.


Plastic 2.5-gallon fish tanks have been praised by the fish-care industry because of its reliability. Manufacturers often brand their plastic tanks as shatterproof and leakproof, which is nothing but true. However, some often overlook the fact that the plastic can be dented without difficulty, and if fixed after the damage, will not look its best.

Another praise about plastic tanks is its ability to look like glass from afar. It gives just as much as clarity as glass, but does not hold as much poise as glass does. Plastic tanks are very cheap, but your guests might also view you the same.


There are fish tanks that offer multiple functions, such as: included filtration, lighting, and heating systems (though these multifunctional tanks can be pretty costly). Then, there are the simple tanks, which do a good job of sheltering the fish, but not so much when it comes to maintaining the home. For these, you would need to look out for your fish more and clean their tank more often.

Why Do You Need a 2.5 Gallon Fish Tank?

No human or animal likes to live in a cramped home; tiny shelters are bound to stunt growth and be unhealthy environments. Likewise, a plain and undecorated home does not grab attention, and though there is little to clean, the routine would have to be done often, which is stressful.

To make sense of it better, fish grow better in bigger tanks. Their natural habitats are usually vast (seas, lakes, etc.), and the best environment for raising fish is one that imitates their original homes. This way, they are able to move around as they please, and find shelter in the plants or accessories of the aquarium.

Some fish can be aggressively territorial, but these are those that can grow massively (like Betta). Some fish may be small and individually need only little space, but usually like to go in schools (groups of fish). So, in scrutinizing either option, 2.5-gallon fish tanks are the animal-friendly way to go about giving your beloved friends the optimal environment they can have.

Speaking of which, plant accessories add flare not only to the fish tank, but also your house. Think of the fish tank as a decoration in your home (but never forget that what lives inside it needs your care)! Decorations were meant to catch the eye of your guests and make your house feel homier. Do not hold back on your pets; give them a place just as good as (or maybe even better than) yours!

Frequently Asked Questions


What is the best fish for 2.5 gallon tank?

The best fish is a plain Betta fish. They can grow up to three inches, and most fish owners recommend giving fish one gallon for every inch they grow. 2.5-gallon tanks are awesome for Betta, because it supplies abundant space, while being able to fit in small spaces.

Other fish, such as Neon Tetras and Goldfish, are not recommendable for these tanks. Neon Tetras are tiny, but healthier when housed in groups, so the tank would not be suitable for an entire school of Neon Tetras. On the other hand, Goldfish can grow up to 14 inches, doing well in 10-gallon tanks. Placing them in smaller tanks impedes their growth.

How many fish in a 2.5 gallon tank?

Typically, only one fish should be placed in a 2.5-gallon tank. Betta fish are hostilely territorial, so it is unadvisable to house them with similar-sized fish. Placing a school of tiny fish is unwise, as their numbers would prohibit them from swimming around liberally. Many fish lovers believe giving fish a small home as animal abuse, so always ponder on the wellness of your fish in the home you want to give it.

What are the dimensions of a 2.5 gallon tank?

The dimensions of a 2.5-gallon tank are dependent on the manufacturer. Some like to increase the height of their tanks so it can efficiently fit on your desk. Others will want to maximize the length and width to fit table tops and aestheticize desktops. There is no singular dimension for all 2.5-gallon tanks, as it is totally up to manufacturers how they desire to design their products.

How often should I clean my 2.5 gallon Betta fish tank?

If you placed a filter in your Betta fish tank, then you may clean it once every two weeks. Even if once-a-week is ideal, it could potentially stress the fish out, as you would have to constantly move it around. Additionally, if you see that the water is getting muddy, try to change it as soon as possible, as dirty surroundings do not promise the survivability of a fish.


With so many seemingly excellent 2.5-gallon fish tanks in the market, it truly would not be straightforward to pick which one fits your home. Nonetheless, you should always remember that the fish tank is more importantly not for you, but your treasured pet fish. You would want to acknowledge how happy the fish will be in its home, as well as how much it can grow. And since fish like to move around like us humans, you should also provide room for your fish to swim around. To really give your little aquatic companion the finest environment it can grow in, you have no choice but to support it with the best 2.5gallon fish tank you can.

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