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How Big is a 20 Gallon Aquarium L x W x H

The manageable size and versatility of a 20-gallon fish tank means they are an excellent choice for most beginners and experienced aquarists.

They are practical, aesthetic, and an affordable option offering an ideal balance between ease of care and creative aquascaping possibilities.

Dimensions of Standard 20 Gallon Fish Tank

Here's everything you need to know about 20 gallon (75 L) fish tanks.

Dimensions in Inches and Centimetres

20 gallon (High): 24" L x 12" W x 16" H (63 x 33 x 43 cm)
20 gallon (Long): 30" L x 12" W x 12" H (77 x 33 x 33 cm)

Weight in Pounds and Kilograms

20 gallon tank weight (empty): 25 pounds (11 kg)
20 gallon tank weight (filled): 225 pounds (102 kg)

Important: Aquarium dimensions vary slightly by brand. So, always confirm the exact size before buying a stand or lid.

There are two different types of fish tanks - glass and acrylic. Glass aquariums are durable and scratch-resistant - but extremely heavy when filled with water. Whereas, acrylic containers are lightweight and cheaper - but prone to scratches.

Even so, always place a large aquarium away from direct sunlight, drafts, and heat sources. This is the best way to avoid algae growth and reduce temperature fluctuations.

Benefits of a 20-Gallon Aquarium

They are twice as big as standard beginner 10-gallon tanks. So, they tend to provide more stable water parameters.
You have enough space for a variety of fish species and aquascapes (e.g. plants and corals).
They are relatively easy to maintain and more affordable - when compared to much larger tanks.

Fish Options for a 20-Gallon Tank

So, now you need to know how many fish you can have in a twenty gallon aquarium that measures 24 inches long, 12 inches wide, and 16 inches high.

Having a container this big means you will be able to keep a variety of fish families. Some of the popular species include:

Community fish, such as GloFish, guppies, mollies, platies, rasboras, and tetras.
Betta fish: It's best to only keep a single betta with other peaceful species (e.g. corydoras).
Cleanup crew: Typical examples include the cherry shrimp, amano shrimp, and nerite snails.
Small cichlids (e.g. German blue rams, shell dwellers).

Remember to apply the stocking rule as close as possible even in a large setup, "one (1) inch of fish per gallon of water". Even so, always consider the adult size of the fish and their bio-load.

Aquascaping and Plant Options

Having a large setup means you have more options for aquarium hardscapes and live plants. For example, rocks, coral, driftwood, and caves are great for aquatic animals to explore and hide inside.

You can add some hardy anubias, semi-aquatic Java fern, mosses, and crypts. Once established, live plants require minimal care and they help to improve the quality of the water. Of course, artificial plants are the cheap alternative for low-maintenance setups.

General Maintenance for Large Tanks

Water Changes: Replace about twenty to thirty percent of the water on a weekly basis.
Filter Cleaning: Rinse the filter media in tank water every two to four weeks.
Gravel Vacuuming: Helps to remove uneaten fish food and debris.
Test Water Quality: Check regularly for high levels of ammonia, nitrite, and nitrate.

Pro Tip: An aquarium that holds 20 gallons (around 75 litres) provides a great balance between manageable size and ease of maintenance. Hence, you can enjoy a diverse aquarium setup while managing your time and budget effectively.