15 Amazing Fish for 20 Gallon Tank (How Many Can You Fit)

Thinking of the perfect fish for your 20-gallon aquarium? Finding the right species for such a compact space requires a bit of thought.

In this guide, we’ll introduce you to 15 of the best fish for 20-gallon aquarium that you can keep and give you some good advice on Choosing and maximizing your tank’s potential. Ready to dive in? Let’s go!”

8 Popular Freshwater Fish for 20-Gallon Tank

Here’s a list of some popular, unique, and good fish species for a 20-gallon freshwater aquarium.

• Guppies
• Neon Tetras
• Platies Fish
• Corydoras Catfish
• Dwarf Gouramis
• Mollies
• Zebra Danios
• GloFish

Guppies

These tiny yet vibrant creatures thrive in spacious environments like your 20-gallon tank. Their easy maintenance and adaptability make them a perfect fit. Their fondness for group living adds a lively dynamic to your aquarium.

Neon Tetras

Neon Tetras are small, vibrant, and easy to maintain. Their size, peaceful temperament, and preference for schooling make them perfect for a 20-gallon tank, allowing them to thrive and exhibit their beautiful colors.

Platies

Platies are small, hardy fish that come in various colors. They are peaceful and can coexist with other peaceful fish. Just like guppies, they are great for beginners.

Corydoras Catfish

Corydoras Catfish are sociable bottom dwellers. A 20-gallon tank is perfect for a small school of these catfish as it provides enough space for them to rummage around the bottom while cohabiting peacefully with other fish species.

Dwarf Gouramis

Dwarf Gouramis are colorful and peaceful. The spaciousness of a 20-gallon tank allows them to comfortably share space with other peaceful fish, and their striking colors add beauty to the tank.

Mollies

Mollies are relatively easy to care for and peaceful. A 20-gallon tank is their minimum requirement, giving them ample room to swim freely and school with their peers, making for a lively and dynamic tank.

Zebra Danios

Zebra Danios are small, lively, and easy to care for. They prefer to be in groups, making a 20-gallon tank a suitable habitat that offers enough space for them to school and engage in their active swimming patterns.

GloFish

GloFish are genetically engineered to glow, adding a burst of color to any tank. A 20-gallon tank provides them with enough space to school and exhibit their vibrant colors, making the tank visually captivating.

Having explored the freshwater world, let’s now dive into the colorful and diverse realm of saltwater fish suitable for a 20-gallon tank.

7 Saltwater Fish Ideas for 20-Gallon Tank

Here’s a list of fish you can add to a 20-gallon saltwater tank, especially for beginners.

• Clownfish
• Firefish
• Royal Gramma
• Pajama Cardinalfish
• Watchman Goby
• Neon Blue Goby
• Flame Angelfish

Clownfish

Clownfish are popular and charming. Their size, temperament, and diet make them well-suited for a 20-gallon tank, allowing enough space for a pair to thrive and display their vibrant colors.

Firefish

Firefish are peaceful and vibrant, and a 20-gallon tank gives them sufficient space to live comfortably.

Their diet preference and love for a solitary life make them a good choice for a 20-gallon tank.

Royal Gramma

A single Royal Gramma is ideal for a 20-gallon tank. Their size, peaceful nature, and diet make them a suitable choice, allowing enough room for them to display their striking colors.

Pajama Cardinalfish

Pajama Cardinalfish are peaceful and easy to care for. The spaciousness of a 20-gallon tank offers them enough room to school and live comfortably.

Watchman Goby

Watchman Goby is peaceful and easy to maintain. A 20-gallon tank provides ample space for it to live comfortably, making it a suitable choice for such a tank.

Neon Blue Goby

Neon Blue Goby are small, vibrant, and peaceful. Their size, diet, and non-schooling nature make a 20-gallon tank a suitable home for them, giving them ample space to thrive and exhibit their bright colors.

Flame Angelfish

A single Flame Angelfish is suitable for a 20-gallon tank. Their size, semi-aggressive temperament, and diet make them a great choice, providing enough space for them to showcase their vibrant colors.

Tips for Choosing Fish for 20-Gallon Aquarium

A 20-gallon aquarium provides ample space for a variety of fish, but it’s essential to choose species that are suitable for this tank size and can coexist harmoniously. Below are some tips and fish recommendations for a 20-gallon aquarium:

Consider the fish’s adult size

Avoid purchasing fish that will grow too large for a 20 gallon tank dimensions. Instead, look for species that remain relatively small throughout their lives.

Keep in mind the fish’s temperament

Some fish are peaceful and can coexist with others, while some can be aggressive or territorial. Research the temperaments of your chosen species to ensure they get along.

Factor in swimming space and territory

Mid-water swimmers, bottom-dwellers, and surface swimmers can be combined to utilize different sections of the aquarium.

Think about maintenance and care levels

Some fish have specific water parameters and dietary requirements, so ensure you can provide for their needs.

Research compatibility

Some fish might have specific requirements or might not get along with certain other species. It’s always a good idea to check which species can coexist peacefully.

Which of These Fish can Live Together in 20-Gallon Tank?

For the freshwater tank, you can consider having guppies, neon tetras, platies, mollies, a few corydoras catfish, and maybe a dwarf gourami or some zebra danios. However, always monitor for any signs of aggression or stress, especially as the fish grow.

For the saltwater fish setup in a 20-gallon tank, limit your selection to the less aggressive and smaller species. Perhaps a clownfish pair, some neon blue gobies, a firefish, and maybe a pajama cardinalfish. However, the Flame Angelfish is best suited for larger tanks.

How Many Fish Can You Keep in a 20 Gallon Tank?

The number of fish you can keep in a 20-gallon tank depends on various factors like the size, diet, and temperament of the fish. However, a good general rule is one inch of fish per gallon of water.

This calculation can guide you when selecting fish for your tank.

For example, a Clownfish that grows to 4 inches in size would require roughly 4 gallons of water.

Conclusion

Choosing the fish for a 20-gallon tank involves careful consideration of compatibility, size, behavior, and the specific needs of each species. It’s crucial to create a balanced and thriving ecosystem within your aquarium to ensure the health and happiness of your aquatic inhabitants.

For a deeper understanding of fish care and setting up a complete aquarium, check out our latest information at “National Park Aquarium“. We’ve got all the information you need!

Kevin Mills

I grew up with a fish tank in my house, and my parents would take me to the local aquarium every chance they got. This passion led me to start NationalparkAquarium.org, which I use to share my love and passion. I am constantly looking for new and innovative ways to improve my aquariums, and I love sharing what I learn with others online.