Why Is Aquarium Size Important?

When it comes to starting an aquarium, size matters more than you might think it would. The size of your tank affects everything from the water quality to the health and well-being of your fish. It can even effect what type and how many fish you can get. Here’s why it’s so important:

• Water Stability: This main seem counter intuitive, but the bigger a tank is, the easier it is to maintain. Larger tanks generally provide a more stable environment because the greater volume of water dilutes toxins more effectively than a small tank would. They also maintain a consistent temperature more easily. In smaller tanks, even minor changes in water quality or temperature can quickly become critical, leading to stress or death for your fish. Think about it, if you add a spoonful of salt to a cup of water, that water is going to be pretty salty. However, if you add a spoonful of salt to a bathtub full of water, you would hardly notice. This same idea applies to fish tanks, if there is more water, it will take more to throw the parameters off balance. And a stable environment helps prevent rapid fluctuations in ammonia, nitrites, and nitrates, which are harmful to aquatic life.
• Fish Health: Fish are sensitive creatures that need a stable environment. A larger tank gives them more space to swim, reduces stress, and allows for a more diverse ecosystem. This is all a lot harder to achieve in a smaller tank. Also, it’s easier to overcrowd a small tank. This is where you have too many fish for the size of the tank. The general rule is to have 1-gallon of tank water to 1-inch of full size fish. Overcrowding in a small tank can lead to stress, aggression, and disease. A stressed fish is a lot more likely to become sick, which can quickly spread to the rest of the fish in the tank.
• Maintenance: Like I said earlier, it might seem counterintuitive, but larger tanks can be easier to maintain. They are much more forgiving of beginner mistakes, like overfeeding or less than frequent water changes. This is because the impact on the overall environment is less severe. Regular maintenance, like water changes and filter cleaning, are essential, but larger tanks provide more of a buffer if something goes wrong, which is a wonderful fallback when it’s needed.

What Does “Gallon” Really Mean in Aquariums?

Before diving into the specifics of tanks and their sizes, it’s important to understand what “aquarium capacity” means. Aquarium sizes are typically measured in gallons or liters, representing the volume of water the tank can hold at any given time. However, the actual amount of water in a tank is usually less than what it’s labeled as. This is due to substrate, decorations, and equipment taking up space where water should be.

For example, a 20-gallon tank may only hold about 17-18 gallons of water after you add the extras, like gravel, plants, and a filter. This is important to consider when planning your tank because there will be less “real” space available for your fish. So, when thinking 1-inch per gallon, you have to think of the real gallons, not just what’s on the label.

Additionally, the actual shape of the tank can affect the swimming space for your fish. A tall, narrow tank might hold the same amount of water as a shorter, wider one, but the swimming area for the fish will be different. You have to consider the types of fish you want and how much swimming space they need when choosing your tank’s shape and size. You wouldn’t want a tall, narrow tank, if you planned on having a lot of Cory Cat’s for instance, because there would be very little surface on the bottom for them to graze.

How Has the Concept of Aquarium Sizes Evolved?

Crazily enough, the general concept of keeping fish in tanks dates all the way back to ancient civilizations, such as the Chinese, who kept goldfish in ceramic bowls as early as 960 AD. However, modern home aquariums, as we know it, started to gain popularity in the mid-19th century, mostly in Europe. Early tanks were small and simple, reflecting the limited knowledge and technology of the time.

As our understanding of aquatic ecosystems grew, so did the size and complexity of our tanks. The development of better filtration systems, lighting, and heating allowed hobbyists to maintain larger tanks that could support more diverse and complex communities of fish and plants — Awesome! Today, aquarists have a wide range of tank sizes and shapes to choose from, catering to both beginners and experienced hobbyists. This evolution has allowed us hobbyists to create more stable and sustainable aquatic environments in our homes.

What Are the Pros and Cons of Different Aquarium Sizes?

Small Tanks (5-20 gallons)

• Pros:
• Lower Initial Cost: Smaller tanks are usually less expensive than their larger counterparts. Because of their size, they require less equipment, making them appealing for beginners on a budget.
• Space-Saving: Small tanks are ideal for people who live in small apartments or areas with limited space.
• Easier to Set Up: Because there is simply just less space, that means the tank needs less water and fewer decorations, leading to a faster setup. They can be a great starting point for learning the basics of fishkeeping.
• Cons:
• Maintenance Challenges: Small tanks require a lot more frequent maintenance to keep the water parameters stable. Even small changes, like an increase in food or poop, can lead to significant problems, such as sudden spikes in ammonia or nitrites.
• Limited Stocking Options: Fewer fish can be kept in a small tank. You will need to be more selective about species. Certain fish that require more swimming space may not do well in a smaller tank.
• Higher Risk for Beginners: Because of the low water volume, mistakes are much less forgiving, making it challenging for newcomers to keep fish healthy. Overfeeding or a missed water change can have rapid, terrible effects in a small tank environment.

• Great beginner starter kits that have everything you need:

• A great 10-gallon starter: Aqueon 10 Gallon Fish Tank

• A great 20-gallon starter: Aqueon 20 Gallon Fish Tank

Medium Tanks (20-55 gallons)

• Pros:
• Balanced Environment: Medium tanks offer a good balance between stability and size, making them a super great option for beginners. They let those who want more options for fish and plants have choices without the complications of a large tank.
• More Stocking Options: Because there is more water in the tank, you can keep a wider variety of fish. You can even start experimenting with live plants and aquascaping, allowing for an even more engaging and visually appealing tank setup.
• Easier Maintenance: The bigger the better. With more water, the tank is less susceptible to parameter and temperature fluctuations.
• Cons:
• Higher Initial Cost: It may be obvious, but generally, the bigger the tank the more investment upfront you will need. This includes more/larger equipment and accessories. You may also need a dedicated aquarium stand, because of the size and weight, which can add to the cost.
• Space Requirements: You need to have a plan before you buy. These tanks take up a lot more space. This might be a consideration if you live in a smaller home or apartment.

Recommended Product: Aqueon Fish Tank Aquarium Essentials Starter Kit for 29 Gallon Tanks – This kit is a great choice for beginners, it offers a good size that’s not too overwhelming, but still allows for plenty of creativity, aquascaping, and fish sizes.

Large Tanks (55 gallons and up)

• Pros:
• Ultimate Stability: If you have a large tank, it will be much more stable. For this reason, large tanks are ideal for sensitive ecosystems or fish. If you’re considering starting a more complex tank, consider going over 55 gallons.
• Unlimited Stocking Options: With a large tank, the fish possibilities are endless. You can keep a few large fish, a ton of medium to small fish, and create a stunning aquascape. This size allows you to have the most creativity and diversity in your aquarium.
• Long-Term Investment: Trust me, once you setup your tank, you’re going to want to visit the local fish store more and more. A large tank gives you space to grow with your hobby, accommodating for new additions and changes. It’s a great choice if you plan to expand over time.
• Cons:
• Higher Costs: Large tanks can be a significant investment, not just in the tank itself but all the equipment, maintenance, and operating costs. They require a lot more powerful filters, heaters, and lighting, which can add up quickly if you are doing right.
• Space and Weight Considerations: They require a solid, reliable stand and a suitable space in your home. You have to also factor in the weight, which can be a concern, especially in apartments or on upper floors. Double, or triple check that your floor can support the weight of a fully stocked large aquarium.

Recommended Product: Tetra 55 Gallon Aquarium Kit with Fish Tank, Fish Net, Fish Food, Filter, Heater and Water Conditioners – A comprehensive kit that includes everything you need to start a large, thriving aquarium.

Real-Life Example: Starting with a Medium Tank

Consider the example of Jane, a beginner aquarist who started with a 20-gallon tank. She chose this size because it offered a balance between manageability and stability. Over time, Jane was able to successfully introduce a variety of fish, including tetras, guppies, and a few live plants. Because the tank was large enough to provide a stable environment but small enough to manage easily, Jane found that she could keep her fish healthy with minimal stress. This experience allowed her to enjoy the hobby and eventually upgrade to a larger tank as her confidence grew.

How Do I Choose the Right Tank Size?

1. Assess Your Space: Measure the area where you want to place the aquarium. Make there’s enough room for the tank, stand, and maintenance tasks like water changes. Consider how the tank will fit with your existing furniture and layout. And make sure you have room around it, so you can get inside and clean the glass and substrate.
2. Consider Your Budget: Take a minute to go online and add up the cost of the tank, stand, filter, heater, lighting, substrate, decorations, plants, chemical additives, and fish. Remember, the bigger the tank, the larger and more powerful the equipment, which can increase costs. It’s better to plan ahead than it is to scrimp and cause your fish to have anything less than a great life.
3. Think About Maintenance: Be honest about how much time you can dedicate to maintaining and cleaning the tank on a weekly basis. Larger tanks require less frequent maintenance and water changes, but they can take more time per session. There is more water to remove, and more substrate to vacuum. Consider whether you can commit to the regular upkeep that a larger tank demands.
4. Research Fish Species: Consider the types of fish you want to keep. Some species require more space and less of crowd, while others thrive in smaller tanks or in large groups. Ensure your tank size can accommodate for the ones you have your heart set on. For example, schooling fish like tetras do better in larger groups, which means a bigger tank would be better. And, if you want to see schooling/shoaling behavior, the fish will need more space to move around.

Now that we’ve explored the benefits and challenges of different tank sizes, you might be wondering how to decide which size is right for you. Let’s dive into a step-by-step guide that will help you make the best choice for your space, budget, and goals as an aquarist.

How Do I Cycle a New Aquarium?

Cycling your aquarium is the process of establishing beneficial bacteria that convert harmful ammonia into nitrite and then into nitrate. Here’s how to do it:

1. Add a source of ammonia: You can use fish food, a piece of shrimp, or pure ammonia to start the cycle.
2. Test the water: Use a test kit to monitor ammonia, nitrite, and nitrate levels. You should see ammonia levels rise, followed by a rise in nitrite levels, and finally a rise in nitrate levels.
3. Wait for the cycle to complete: This process can take 4-6 weeks. Once ammonia and nitrite levels drop to zero and nitrate levels stabilize, your tank is cycled.
4. Perform a water change: Before adding fish, perform a 50% water change to lower nitrate levels.
5. Introduce fish gradually: Start with a few hardy fish and add more over time as the tank stabilizes.

For a more detailed explanation, take a look at our article on the Fastest Way to Cycle a Fish Tank.

Frequently Asked Questions About Aquarium Size

What size tank should I start with as a beginner?

As a beginner, it’s generally recommended to start with a tank between 20-30 gallons. This size offers a good balance between stability and ease of maintenance. It’s large enough to provide a stable environment for your fish but not so big that it becomes overwhelming to manage. Starting with a medium-sized tank also gives you more flexibility in the types of fish and plants you can keep.

Can I start with a smaller tank, like a 5-gallon or 10-gallon?

While it’s possible to start with a smaller tank, such as a 5-gallon or 10-gallon, they can be more challenging for beginners. Small tanks are less forgiving of mistakes and require more frequent maintenance to keep the water parameters stable. If you choose to start with a small tank, be sure to select hardy fish that are well-suited to smaller environments, and be prepared for the extra work involved in keeping the tank healthy.

Is a bigger tank always better?

In many ways, a bigger tank is better because it provides more stability, more options for stocking, and a larger margin for error. However, bigger tanks also come with higher costs and require more space and maintenance. If you have the budget, space, and time to dedicate to a larger tank, it can be a rewarding choice. But it’s important to choose a tank size that fits your lifestyle and experience level.

How do I know if my floor can support a large aquarium?

Aquariums can be very heavy, especially when filled with water, substrate, and decorations. A fully stocked 55-gallon tank can weigh over 600 pounds. It’s important to ensure that your floor can support this weight, particularly if you live in an older home or an apartment. If you’re unsure, consult with a structural engineer or place the aquarium near a load-bearing wall on the ground floor to distribute the weight more evenly.

What Are the Best Practices for Starting with Your Chosen Tank Size?

• Cycle Your Tank: Before adding fish, make sure to cycle your tank to establish beneficial bacteria that break down waste. This is crucial for maintaining a healthy environment. Cycling can take several weeks, but it’s essential to avoid “new tank syndrome,” which can be deadly to fish. Learn more about cycling here.
• Stock Gradually: Start with a few hardy fish and gradually add more as your tank stabilizes. Avoid overstocking, especially in smaller tanks. Overstocking can lead to poor water quality and stressed fish. It’s better to add fish slowly and monitor how your tank adjusts.
• Regular Maintenance: Perform regular water changes, clean the filter, and monitor water parameters. This is vital for keeping your tank in top condition. Consider using a complete aquarium test kit to monitor your aquarium. Regular testing helps you catch any issues before they become serious problems.