10 Best 20-gallon Long Aquariums [2025]

Finding the best 20-gallon long aquariums can be a daunting task, especially with the plethora of options available on the market today. With varying styles, features, and price points, narrowing down the choices to meet your specific needs can be overwhelming. To simplify your search, we meticulously shortlisted 10 products based on quality, customer reviews, and functionality, ensuring that our list not only highlights the top contenders but also saves you time and hassle in selecting the perfect aquarium for your home or office.

Top 10 20-gallon Long Aquariums In The Market

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20-gallon Long Aquariums Review

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Our Review Process

To ensure you get reliable product recommendations, we follow a detailed review methodology that includes:

• Market Research: Scanning best-selling and trending products in this category.
• User Feedback: Reviewing customer reviews, star ratings, and complaints.
• Hands-On Testing: Trying select products ourselves when feasible.
• Feature Comparison: Evaluating specs, durability, pricing, and safety.
• Expert Opinions: Consulting with niche experts or credible reviewers.

We independently select the top 10 options based on value, quality, and usability. To learn more, visit our detailed review process.

Key Considerations Before Buying a 20-Gallon Long Aquarium

1. Space Availability

Before purchasing a 20-gallon long aquarium, it’s crucial to assess the space where you plan to place it. Measure the area to ensure that the aquarium will fit comfortably. Consider not just the footprint of the tank, but also the height and surrounding space for maintenance and viewing angles. A 20-gallon long tank typically measures around 30 inches in length, so ensure you have a surface that can support its weight when filled with water and decorations.

2. Weight and Support

The weight of a filled aquarium can be substantial. A 20-gallon tank, when filled with water and substrate, can weigh upwards of 200 pounds. Ensure that the stand or furniture you choose can support this weight, and avoid placing it on weak surfaces. A dedicated aquarium stand is often the best option, as it is designed to distribute the weight evenly and provide stability.

3. Filtration and Heating Needs

A 20-gallon tank will require appropriate filtration and heating systems to maintain a healthy environment for your aquatic life. Research suitable filter options that can handle the tank’s volume and ensure they provide adequate water movement and mechanical, chemical, and biological filtration. Similarly, consider a heater that can efficiently warm the water to the desired temperature for the fish and plants you plan to keep.

4. Aquascaping and Decor

Think about how you want to aquascape your tank. The long shape provides ample space for creative designs, but you’ll need to choose decorations, plants, and substrate that fit your aesthetic and the needs of your aquatic inhabitants. Ensure that any decor you select is safe for fish and won’t leach harmful substances into the water. Additionally, consider the type of plants that will thrive in your chosen lighting conditions.

5. Fish Compatibility

When selecting fish for your 20-gallon long aquarium, consider the tank’s dimensions along with the temperaments and sizes of the species you wish to keep. Research bioload requirements, compatibility with other fish, and the ideal number of each species that can thrive in your tank. Overcrowding can lead to stress and health issues, so be mindful of your selections.

6. Maintenance Requirements

Every aquarium requires maintenance, and a 20-gallon long tank is no exception. Consider how much time you can dedicate to regular tasks such as water changes, filter cleaning, and monitoring water parameters. Easier maintenance may be achieved by selecting low-maintenance plants and fish, making the hobby more enjoyable and less time-consuming.

7. Initial Setup and Ongoing Costs

Purchasing a 20-gallon long aquarium involves more than just the tank itself. Calculate the total costs, including the filter, heater, substrate, decorations, plants, and the fish you want to keep. Additionally, account for ongoing expenses such as food, water conditioners, and test kits for monitoring water quality. It’s essential to budget for both the initial setup and the ongoing costs to ensure a successful aquarium experience.

8. Lighting Requirements

Lighting is a critical aspect of any aquarium setup, affecting both fish and plant health. Determine whether you will use standard fluorescent bulbs, LED lights, or specialized plant lights, and ensure they are suitable for the depth and type of plants you want to keep. The light source should provide adequate illumination for photosynthesis if you plan on including live plants while also considering the needs of your fish species.

FAQs

What are the dimensions of a 20-gallon long aquarium?

A typical 20-gallon long aquarium measures approximately 30 inches in length, 12 inches in width, and 12 inches in height. These dimensions provide a spacious environment for fish and aquatic plants.

What type of fish can I keep in a 20-gallon long aquarium?

You can keep a variety of freshwater fish in a 20-gallon long aquarium. Suitable options include small community fish like guppies, tetras, and corydoras. Be sure to research compatibility and ensure that the total adult size of the fish does not exceed the tank’s capacity.

What equipment do I need for a 20-gallon long aquarium?

Essential equipment for a 20-gallon long aquarium includes a filtration system, a heater (if keeping tropical fish), an aquarium light, substrate, and decorations or plants. You may also want to have a water testing kit and maintenance tools such as a net and siphon.

How often should I perform water changes in a 20-gallon long aquarium?

It is recommended to perform water changes every 1-2 weeks, changing about 10-20% of the water each time. This helps maintain water quality and reduces harmful toxins that can build up over time.

What substrate is best for a 20-gallon long aquarium?

The best substrate for a 20-gallon long aquarium depends on the type of fish and plants you plan to keep. For general freshwater setups, a fine gravel or sand substrate works well. If you plan to keep live plants, consider using a nutrient-rich substrate designed for planted tanks.

Can I use a 20-gallon long aquarium for a saltwater setup?

Yes, a 20-gallon long aquarium can be used for a saltwater setup, but it requires specific equipment such as a protein skimmer, appropriate lighting, and saltwater test kits. Keep in mind that saltwater tanks can be more challenging to maintain than freshwater tanks.

How many fish can I have in a 20-gallon long aquarium?

A general rule of thumb is to allow 1 inch of adult fish per gallon of water. However, factors such as fish species, temperament, and filtration can affect stocking levels. For a community tank, consider keeping around 10-15 small fish while ensuring they are compatible.

What plants are suitable for a 20-gallon long aquarium?

Many aquatic plants are suitable for a 20-gallon long aquarium, including Java fern, Anubias, Amazon sword, and cryptocoryne. These plants can enhance the aesthetics of your tank and provide hiding spots for fish.

How do I cycle my 20-gallon long aquarium?

Cycling an aquarium involves establishing beneficial bacteria that break down harmful ammonia and nitrites. You can cycle your tank using fishless methods (adding ammonia) or by using hardy fish. It typically takes 4-6 weeks for a tank to fully cycle.

What type of filter is best for a 20-gallon long aquarium?

Canister filters, hang-on-back filters, and sponge filters are all good options for a 20-gallon long aquarium. Choose a filter with a flow rate suitable for the tank size, ideally around 4-5 times the tank volume per hour.

The Bottom Line

In conclusion, selecting the right 20-gallon long aquarium can significantly enhance your aquatic experience, whether you’re a novice or an experienced aquarist. Our curated list of the top 10 products reflects a careful evaluation of various essential factors, including tank design, material quality, filtration systems, and user reviews. By focusing on these key criteria, we aimed to present options that not only meet aesthetic preferences but also support the health and well-being of your aquatic life.

By following our recommendations, you can simplify your decision-making process and choose an aquarium that aligns with your needs and expectations. Each product on our list has been vetted for durability, functionality, and overall user satisfaction, ensuring that your investment will provide a thriving environment for your fish and aquatic plants. We hope this guide serves as a helpful resource as you embark on your journey in the world of aquariums, making it easier for you to create a beautiful and harmonious underwater ecosystem in your home.