How to Choose the Right Sized Fish Tank, and Our Top Picks

Written by Sarah Psaradelis
Updated: May 27, 2024


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Choosing the right-sized aquarium can be quite challenging. There is a range of different types of aquariums of various sizes in the market. Not every tank is suitable for each species of fish, though. Tank size is often a confusing topic in the aquarium community. With so many different opinions and options, it can be difficult to decide what size you should buy.

The size of your tank should be comfortable and beneficial for your fish. Don’t focus first on what takes up the least space or looks the most aesthetic. Many experienced fish keepers and experts in the field will use the term “the bigger, the better”. This statement couldn’t be truer.

Not only is it easier to care for a large aquarium because the large volume of water allows more room for error, but they are less likely to become overcrowded. Overcrowding could lead to constant stress or disease outbreaks. Large aquariums also provide the fish with more space to display their natural habits.

Let’s get into some of the best fish tanks you can purchase, along with what experts and scientists say on the matter of tank size.

  1. FLUVAL Chi Aquarium Kit
    • 3-D cube design to make viewing easy
    • Mounted on pedestal
    • LED lights included with daylight and moonlight features
    • Hidden filter included
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  2. Tetra Glass Aquarium
    • 55-gallon capacity.
    • Variety of customization options from Tetra available (but sold separately).
    • Comes in smaller sizes.
    Check Amazon
  3. Landen 72.2 Gallon Rimless Low Iron Aquarium Tank
    • Massive 72.2-gallon capacity.
    • Made from low-iron glass, making the view clearer than a standard fish tank.
    • Rimless design.
    • Comes in a wide variety of sizes.
    Check Amazon

A-Z Animals Top Picks for Fish Tanks

#1 Best Overall: Fluval Chi Aquarium Kit

The best overall fish tank is the Fluval Chi Aquarium Kit.

Fluval is a popular name when it comes to fish products. They make filters, among other items to make your betta happy and healthy. This aquarium comes in a 3-D cube design that gives you 360-degree views of your aquatic friend. 

While there are plenty of tanks on the market, this one takes the top spot because of the crystal clear glass design that is situated on top of a pedestal. This makes the tank look like it’s suspended in air, defying gravity. 

There are also LED lights included that have daylight and moonlight features. The white light setting is best used during the day and the blue should be turned on in the evening hours. Also, included with the aquarium is a filter with three water treatments to ensure your betta is swimming in clean and healthy water.

However, customers have reported that it is difficult to find replacement parts for the LED lights if the bulbs go out.

Pros and Cons of Fluval Chi Aquarium Kit

This aquarium has a 3-D cube design.It can be difficult to source replacement parts and bulbs for the LED lights.
It features LED lights with daylight and moonlight settings.
It comes with a powerful filtration system.
Overall Best
FLUVAL Chi Aquarium Kit
  • 3-D cube design to make viewing easy
  • Mounted on pedestal
  • LED lights included with daylight and moonlight features
  • Hidden filter included
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2. Best for Betta Fish: Aqueon LED Fish Aquarium Starter Kit

If you have Bettas then the perfect tank is Aqueon LED Fish Aquarium Starter Kit.

This fish tank from the brand Aqueon is affordable and suitable for small fish such as bettas. This tank is great for beginners and experienced fish owners alike. It is 20-inches long, has a capacity of 10 gallons and can fit multiple goldfish comfortably. The lid is secure, one of the things that reviewers liked most about this tank.

The sides are glass so make sure that you have a sturdy place to put the tank that can support the weight, including the water. The lid has an opening on the top that is large and great to scatter food for multiple fish. The included LED light mounts on the top to illuminate your fish tank and the heater and filter work to keep the water clean and safe for your fish. You will need to add the aquarium elements like rocks, plants, and other interactive accessories separately.

It also features a QuietFlow filter, and when it’s time to change it, a built-in LED light blinks red. This makes it really easy to keep the water clean. However, you may need to make some adjustments to the filter to ensure that the current produced from it is not too strong for long-finned betta varieties. Attending to the water in your fish tank is one of the most important aspects of owning a fish. The thermometer and 50W pre-set heater make it easy to monitor the water temperature, another important task. This kit even comes with a sample of fish food and a net to transfer your fish into and out of the tank when needed.

Furthermore, some customers have reported that the hood is made from thin plastic that is not very durable.

Pros and Cons of Aqueon LED Fish Aquarium Starter Kit

This tank comes as a complete kit with a filter, built-in heater, thermometer, hood, fish food, fish net, and LED lighting.The hood is made from thin plastic and is not durable.
It has a 50W pre-set heater.You may need to adjust the filter so that the current is not too strong for bettas.
It features a QuiteFlow filter with an LED light to indicate when it needs changing.
It has a secure lid with a large opening for feeding the fish through.

3. Best for Size: Tetra Glass Aquarium

If you’re looking for a tank that offers the best sized space for larger fish then we recommend the Tetra Glass Aquarium.

This 55-gallon fish tank is perfect for some larger species of fish, such as a group of three goldfish, a large school of tetras, angel fish, or even a cichlid. It has a lot of space for decorations, a good filter, heater, and you can stock more small fish varieties in the space if they are compatible.

The glass is clear and strong, with black rims for extra support and to make the tank look more modern. This tank is fully customizable since it does not include any other aquarium equipment in the price, but the tank’s design allows you to add an assortment of accessories depending on the type of fish you plan to keep inside. Although, this does mean that it is best suited to experienced fish owners, and it may make it be more expensive in the long run.

Pros and Cons of the Tetra Glass Aquarium

This tank has a capacity of 55 gallons.It is unsuitable for beginners as it does not contain any other aquarium equipment.
It is ideal for larger fish.
It features black rims which provide extra support.
It is fully customizable.
Best for Size
Tetra Glass Aquarium
  • 55-gallon capacity.
  • Variety of customization options from Tetra available (but sold separately).
  • Comes in smaller sizes.
Check Amazon

4. Best for Large Fish: Landen Rimless Low Iron Aquarium Tank

The best tank for large fish is the Landen Rimless Low Iron Aquarium Tank which has a massive capacity.

This is a large 72-gallon fish tank made of low-iron glass, which offers a much clearer view than standard aquarium glass. The tank looks crystal clear and has no green hue that you see with your typical fish tank glass. It might be on the pricier side, but it is a good investment if you are looking for a large, simple, and high-quality fish tank to house larger fish species in, such as goldfish, cichlids, and even some marine fish.

The low iron glass pieces have been glued together without leaving bubbles or visible silicone pieces that could ruin the appearance of the tank. The tank undergoes strict quality testing before being shipped out and it includes a nanofoam pad to help keep the aquarium level which is important for such a large fish tank. It does have the Landen branding from the manufacturer in one corner, but you can move the tank, so the label is at the back and not displayed in the front if you do not want it to disturb the aesthetics of your aquarium.

Once again, this tank is completely customizable as it does not come with any other aquarium products, although this does make it unsuitable for beginners.

Pros and Cons of the Landen Rimless Low Iron Aquarium Tank

The tank has a massive 72 gallon capacity.It is not suitable for beginners as it does not come with any other aquarium products.
It is made with low-iron glass which is clearer than standard aquarium glass.
It does not have any visible silicone pieces.
It comes with a nanofoam pad to keep the tank level.
Best for Large Fish
Landen 72.2 Gallon Rimless Low Iron Aquarium Tank
  • Massive 72.2-gallon capacity.
  • Made from low-iron glass, making the view clearer than a standard fish tank.
  • Rimless design.
  • Comes in a wide variety of sizes.
Check Amazon

How to Choose the Right Sized Fish Tank

As a fish keeper, you might be asking yourself what the right-sized fish tank will be for you. The answer will depend entirely on the type of fish you plan to keep.

There are also three things to take into consideration when choosing the right-sized tank for your fish – the dimensions, the type of fish, and the stocking ratio that will determine if the tank size is ideal.

Tank Dimensions

Fish tanks are available in a variety of sizes, from small to very large. The dimensions will determine how large the tank will be ranging anywhere from one gallon to as large as 250 gallons. The tank could either be tall, square, or rectangular depending on the space you have available for the tank and the type of fish you plan to keep. Determine the shape of the tank based on your fish’s swimming patterns.

When purchasing a fish tank, always make sure that you double-check the dimensions of the tank to ensure that they measure up to the volume of water the tank claims to hold. Since most fish are better suited for long, rectangular tanks, this will be the best option if you are buying a species of beginner fish like goldfish, bettas, or livebearers.

Type of Fish

This is one of the most important considerations when choosing a fish tank. That’s because the type of fish you keep will depend on the size of your fish tank. Most fish grow quite large and require a tank that is big enough to support their size, waste output (bioload), and group behavior. If you are getting a large-growing social fish like goldfish, they will require a larger tank than a small, solitary male betta fish.

A tank that is suitable for bettas such as a five or 10-gallon tank will be way too small for goldfish who can grow between 10 to 12 inches in size and should be kept in groups. Even small schooling fish such as guppies and tetras will need a big tank because their large numbers would be overstocked in a small tank, leading to increased stress and accumulating waste in such a small volume of water that does not support the number of fish in the tank.

Stocking Ratio

The stocking ratio or gallons per fish rule is just as important when choosing the right-sized fish tank. Fish tanks can quickly become overstocked or “overcrowded”. If that happens, it can become difficult for you as the fish keeper to maintain. It also creates an undesirable and stressful environment for the fish.

Social species of fish will need to be kept in groups so that they can feel safe and form a school with their own species. These fish should not be kept as individuals, and thus, need a larger tank. Overstocking can happen with social fish or when you mix a variety of different fish species and invertebrates (shrimp or snails).

If you plan to keep a mixture of tropical fish like livebearers, and bottom-dwelling fish like Plecostomus’s, along with some snails, you will need a much larger tank to support them and make sure they have enough space. The more fish you add to your tank, the larger the tank should be.

Always consider the minimum tank size requirements for your fish species, including the correct stocking ratio to ensure that the tank does not become overstocked.

Why the Size of the Fish Tank Matters

New research on fish behavior is increasing, which is leading fish keepers to understand why fish do not belong in old-school aquariums that were too small. Fish have proved to be intelligent and sentient beings that have the ability to feel emotions, remember situations, and respond to their environment.

According to Professor Culum Brown at Macquarie University, “fish are more intelligent than they appear”. Many people think when purchasing a fish that it will be healthy in a small tank, bowl, or jar. Professor Brown, though, concluded extensive evidence of behavioral and cognitive sophistication, as well as pain perception, in fish. This suggests that the best practice would be to lend fish the same level of protection as any other vertebrate.

This means that we cannot overlook a fish’s living conditions just because we do not fully understand them. Their environment in captivity tank size, tank mates, and water quality play a role in their ability to thrive. It is important to hold the same morals and compassion for our aquatic friends, just as we would for our dogs or cats.

Remember that the fish tank you provide is the only space the fish has to live its whole life. It is up to us as fish keepers, then, to ensure that they are cared for properly. Although fish don’t communicate in a way that we understand, they show signs of stress and illness in poor environments.

So, you might still be wondering why bigger fish tanks are better than smaller ones. While the larger the tank is, the more volume of water there is. This gives the fish more space, helps to dilute their toxic waste, creates a balanced environment, and helps prevent stress from overstocked conditions. Tank size is not only about what’s easier, but what is ethical and better for the fish to thrive in.

Poor conditions are the leading cause of fish deaths aside from disease. Finding the right tank to provide your fish a comfortable home will allow them to thrive and not just survive.

About the Author

Sarah is a writer at A-Z Animals primarily covering aquatic pets, rodents, arachnids, and reptiles. Sarah has over 3 years of experience in writing and researching various animal topics. She is currently working towards furthering her studies in the animal field. A resident of South Africa, Sarah enjoys writing alongside her pets and almost always has her rats perched on her shoulders.

How to Choose the Right Sized Fish Tank, and Our Top Picks FAQs (Frequently Asked Questions) 

Are fish happy in small tanks?

It is difficult to determine if a fish is happy since scientists have not done much testing and research on whether fish can show this emotion.

However, we do know that small tanks or aquaria such as bowls, jars, and vases can cause a fish to become stressed due to poor conditions and water quality.

They will show signs of stress and failure to thrive by not growing as quick or as large as they should, also known as stunting. They may also be prone to more diseases due to increased stress and appear to have difficulty moving the tank. Some fish that are stressed due to their conditions may also try to jump out the top of the aquarium.

Even if a fish looks fine and you are doing the best to maintain the aquariums water quality, space availability will still be an issue as fish need space to grow and swim properly.

Can you keep fish in a bowl?

It is not recommended to keep any species of fish in a fishbowl, vase, or jar. They typically don’t hold more than a few gallons of water and there is hardly any space left for equipment and accessories. The water quality will also be more difficult to maintain, and ammonia fluctuations can happen quickly. Many bowls do not meet the minimum tank size requirements for fish species.

What can you keep in small aquariums?

If you have a jar, vase, or bowl that you want to keep something inside of, small invertebrates like neocaridina shrimp and even small species of snails like ramshorns will be a good option. This is if the small aquaria are heater and filtered according to their requirements.

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