The Fish Guru

Building a Thriving 20 Gallon Aquarium: A Comprehensive Guide

When it comes to setting up your own aquarium, it can be overwhelming to decide on the perfect size, filtration system, and lighting setup that will allow your fish and aquatic plants to thrive. With a 20-gallon tank, you can create a beautiful and eclectic aquarium that won’t overwhelm your space or your budget.

In this article, we will discuss what to look for when choosing the best 20-gallon tank for your needs, and highlight some of the top 20-gallon tanks available in the market.

Criteria for Choosing the Best 20 Gallon Fish Tank

To ensure that your aquarium is both easy to maintain and sustainable for the fish and other aquatic animals living inside, you need to consider several factors before you purchase a tank.

Aquarium Layout

The design of a tank is an essential factor to consider when buying a 20-gallon fish tank. A rimless aquarium is a top choice for enthusiasts who want to create a minimalist aesthetic for their aquarium.

They offer an unobstructed view of the fish and take up less space due to their sleek design. They can be a bit more expensive than other options, but still generally affordable for hobbyists who want a premium look.

On the other hand, those on a tight budget can opt for a traditionally styled fish tank that includes hoods.


Choosing the right type of filtration system is crucial for keeping the water in your tank clean and healthy. An all-in-one tank, which includes a built-in filtration system, might be a convenient option for those who need to save space.

These tanks typically incorporate a 3-stage filtration system, which includes mechanical, chemical, and biological filtration, ensuring that your aquatic life is healthy and happy. Power filters are another popular choice since they provide excellent water filtration and maintenance.

In contrast, an internal filter is suitable for aquariums with naturally filtered tanks that won’t need a lot of maintenance.


Aquarium lighting is critical for the growth of aquatic plants, corals, and other animals inside your tank. Low light aquarium plants and soft corals require lighting in the correct spectrum and par values for optimal growth.

Therefore, it is vital to invest in high-quality lighting systems to help your plants thrive. Many of the newer tanks come with LED lights, which are both highly effective and energy-efficient, making them a suitable choice for most aquariums.


It’s essential to consider the cost when purchasing a 20-gallon tank. Determine your budget and stick to it.

A durable setup that is affordable and won’t break the bank is ideal for people with budget constraints.

Best 20 Gallon Fish Tanks

Now let’s take a closer look at some of the best 20-gallon fish tanks available in the market today:



UNS 60U is a well-built rimless tank that has exploded in popularity for its aesthetic appeal. The clear glass allows a clear view of the fish and aquatic plants inside and is a popular choice among fish enthusiasts who are drawn to the minimalistic design.


UNS 60U is on the pricier side, but you’re guaranteed to get a quality product that will last a long time.

Waterbox 20 Cube


Waterbox 20 Cube is an all-in-one fish tank that features a built-in filtration system, filter sock, and a sleekly designed glass cube. The

Waterbox 20 Cube is perfect for both Saltwater systems and freshwater planted tanks.

It is also easy to maintain and provides an excellent environment for fish and aquatic plants. Although a bit on the expensive side, this tank is a worthwhile investment for those who prioritize quality.

Aqueon 20-Gallon Aquarium Kit

If you are on a tight budget, the

Aqueon 20-Gallon Aquarium Kit is a must-have for budget-conscious fish enthusiasts. The kit includes all the necessary equipment, such as a power filter, hood, and heater, making it a complete set.

Aqueon is a well-known brand in the industry, and their equipment is high in quality, making this a great choice for those looking to save.

Red Sea Max Nano

If you’re looking to create a nano reef tank, the

Red Sea Max Nano is an excellent choice. It features ultra-clear glass and beveled edges that provide an unobstructed view of the fish and coral inside the tank.

With a compact design, this tank is perfect for small spaces while still providing a filtration system, protein skimmer, media shelf, and LED lighting system. Additionally, the Reefbeat app provides a convenient way for you to stay in control of all facets of your reef tank’s health.

Innovative Marine Fusion Pro 20

Another all-in-one tank that is highly popular among enthusiasts is the Innovative Marine Fusion Pro 20. This tank comes with additional features like a mesh lid, micro glass cleaner, algae scraper, and a Mighty Jet DC water pump that creates waves in your tank.

It is highly customizable and low maintenance, making it a suitable choice for beginners.

Aqueon NeoGlow Tank


Aqueon NeoGlow Tank is perfect for those who want fluorescent glow or “Glofish.” It provides a specialized LED lighting system that is suitable for artificial plants, rocks, gravel, and aquatic animals that have a fluorescent glow. It is also affordable, making it a great budget option for those looking to add a bit more color to their aquarium.

Aqueon 20 Gallon Long Tank

If you’re interested in a more extended tank, the

Aqueon 20 Gallon Long Tank is a fantastic option. It offers greater length than most 20-gallon tanks, making it ideal for lovers of aquascaping who want greater creativity with their layout.

It features rimless glass and an all-in-one system, which is perfect for those on a tight budget.


In conclusion, choosing the best 20-gallon fish tank doesn’t need to be complicated. By considering the size, filtration system, and lighting setup you want and how much you’re willing to spend, you can find the right tank for you.

Whether you’re looking for a budget-friendly option, an all-in-one tank, or a nano reef tank, the above list features some of the best 20-gallon tanks available in the market today. With the right tank, you can create a beautiful and thriving aquascape in your own home that you will enjoy watching and maintaining for years to come.

Setting up a 20-gallon aquarium requires attention to even the smallest details. While it may seem like a small, simple tank, it is not always easy to keep it clean and healthy for both fish and aquatic plants.

In this article, we will focus on the best fish for a 20-gallon aquarium and how to set it up for optimal success.

Best Fish for a 20 Gallon Aquarium

Freshwater Tanks

When it comes to freshwater fish for a 20-gallon tank, there are a lot of species to consider. Small, peaceful fish like nano fish, guppy fish, rasboras, danios, and small tetras are great options because they don’t take up too much space and won’t be aggressive towards each other.

For those looking for a bit more of a challenge, freshwater pea puffers can make for an exciting addition to your freshwater tank.

Nano Fish are incredibly small and colorful, which makes them a perfect choice for a 20-gallon aquarium.

They are easy to care for, have low bioload, and require minimal filtration. Guppy fish are also colorful and come in an array of patterns and designs.

They are similar to nano fish in their ease of care and reputation as hardy fish and can quickly adapt to any environment. Rasboras, Danios, and small tetras are schooling fish that are peaceful and like to swim together, making them an ideal option for a community tank.

Freshwater Pea Puffers, on the other hand, are tiny fish that have a playful personality that makes them attractive to enthusiasts.

Saltwater Tanks

Saltwater fish can be challenging to keep, but there are a few species that are suitable for a 20-gallon saltwater tank. Clownfish are a popular choice since they are small, attractive, and relatively hardy.

They are also a relatively peaceful and non-aggressive species but should not be kept with other clownfish as they will aggressively defend their territory. Damselfish are another good option as they are hardy, active, and brightly colored.

They are also very affordable and easy to care for. If you’re interested in creating a nano reef tank, various species of Zoas are worth considering.

These colorful, hardy, and relatively easy-to-care-for corals can be a great addition to a small reef tank. Additionally, having clean up crew consisting of a combination of hermit crabs and snails is a great way to keep up with the unwanted waste always present in any aquarium.

Setting Up a 20 Gallon Aquarium



When it comes to setting up a 20-gallon aquarium’s filtration system, canister filters and 3 stage filters are popular choices because they are efficient, easy to use, and provide a high water-quality standard. The OASE Biomaster 350 and the Fluval 307 are both excellent options that can filter tanks up to 70 gallons.

The 3-stage filtration system includes mechanical, chemical, and biological filtration that guarantees excellent water quality.

Aquarium Heaters

A quality heater is essential to keep your aquarium water at the right temperature. Many heaters brands and models are available, so it’s essential to choose the one that suits your budget, tank size, and feature requirements.

Eheim and OASE filters and controllers, Inkbird, and wifi capability controllers all provide excellent options, giving you versatile control of your heater and other aquarium equipment. Aquarium


Lighting is another essential component to consider, which helps to keep corals or live plants healthy. There are plenty of options available, but the AI Prime and Current USA IC Pros are two popular choices among aquarists.

These LED lights provide the ideal spectrum for the plants and corals in your tank. When it comes to lighting for a saltwater tank, you need to be mindful of the light and the growth of algae but adding a skimmer can greatly minimize this issue.


Driftwood is a great option that provides an aesthetic appeal and can also provide a natural form of filtration. Live rock, made of large pieces of calcium carbonate, is not only great for the look but serves as a natural filter bed and provides significant benefits for the water chemistry inside your tank.

Live Plants or Corals

If you want to add live plants or corals, it’s important to remember that they will need adequate lighting and will also require daily maintenance. Beginners can start with easy-to-care-for live plants like Anubias, Java Fern, and Cryptocoryne.

If you are interested in adding corals to your tank, it’s better to start with beginner coral that is easy to maintain and requires less technical diligence.


A 20-gallon aquarium may be small, but with the right setup, you can create an attractive, healthy, and sustainable ecosystem for both fish and aquatic plants. By determining which fish is best suited to your tank and the correct equipment, such as filtration systems, heaters, lighting, decorations, and live plants, achieving your desired results becomes effortless.

With proper management, hard work, and dedication towards upkeep, you can create an aquarium that is not only beautiful but thriving for years to come. In this article, we discussed the essential points to consider when setting up a thriving 20-gallon aquarium.

We explored the criteria for selecting the best 20-gallon fish tank, including an aquarium’s layout, filtration, lighting, and price. We also listed some of the best freshwater and saltwater fish species suitable for a 20-gallon aquarium.

Finally, we discussed setting up a 20-gallon aquarium, including the filtration system, aquarium heater, lighting, decorations, and live plants or corals. It’s essential to consider all these aspects and give them the right attention to creating an aesthetically pleasing and sustainable aquarium that will last for years to come.

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