How Many Fish In A 5 Gallon Tank? Here’s What You Need To Know

Successfully stocking your 5-gallon nano tank is a rewarding and fulfilling experience especially if you’re a beginner. It will be worth the effort to see your fish thriving even in a small tank. But then, you may be wondering:  how many fish in a 5 gallon tank?

Generally, the number of fish to keep in a tank this small depends on the types of fish you keep in it. We’ll discuss this and more in this 5-gallon tank set up guide.  Keep reading until the end and learn. 

How Many Fish In A 5 Gallon Tank: General Guidelines

Five-gallon tanks make any room alive! Decorate it with plants, substrate, and stone, and of course your pet fish.  They’re a nice addition to your home if you have a small space and they are the smallest to possess for fishkeeping.

However, the water quality and environment can easily become stressful for your fish if you don’t pay close attention to the number of fish in your tank.

As a general rule, you can keep four to six fish in this tank size, but they must not be larger than two inches each.

For smaller fish, you can apply the one-inch fish per gallon.

However, I don’t recommend keeping fish that grow larger than two inches in a five-gallon tank.

For example, avoid keeping goldfish Rasboras and Tetras that can grow to six inches in a 5-gallon tank.

Best Fish Species For A 5-Gallon Tank

Before buying fish for a 5-gallon aquarium, know what fish species are compatible for it. Check them out in the following.

1. Mollies (Poecilia Sphenops)

Lovely and calm, mollies are also a great choice for a nano tank because of their peaceful character. 

This fish is an omnivore, so it feeds on both plant material and live prey, too.

They’re easy to care for and can make an aquarium more colorful. Under the right conditions, they can live up to three years and grow up to four inches.

However, female mollies are not suitable for a small tank because they give birth frequently. Keep only a male fish in your tank to avoid overstocking it.

2. Betta Fish (Betta Splendens)

This fish can also be kept in a small tank, so you might want to consider it to stock your nano aquarium.

However, make sure that you keep them with fish of the same temperament because they’re semi-aggressive. Peaceful species might not suit a tank with a betta fish.

They require a tropical and freshwater condition, have a lifespan reaching up to seven years, and can grow up to four inches.

Take note that they’re also highly-territorial. Keeping males in the same tank will cause fights and lead to fatalities, too.

You can keep a male betta with some cherry shrimps for a lovely tank!

3. Neon Tetras (Paracheirodon Innesi)

Do you want a colorful and lively display? Then, consider this brightly-colored fish!

They have a peaceful temperament and easy care level. Remember that their diet is for omnivores and water conditions should be tropical and freshwater.

They can live for up to three years if taken care of properly and grow up to 1.6 inches. 

A little note: They’re shoaling fish, so you might not have any more room for other types of fish in your tank if you would choose them. 

4. Endler’s Livebearers (Poecilia Wingei)

The tropical freshwater fish is suitable for a small tank and beginners. 

They have a peaceful disposition and are easy to care for. You can choose to keep them with the same species or with other fishes.

Also, they are a nice addition to your small tank because of their beautiful color.

They have an omnivore diet, can live between three to five years, and reach up to one inch in length.

Endler’s Livebearers, which are shoaling fish, live harmoniously with a group of their own. 

But while they can live in a small tank, these species would love a larger aquarium with lots of plants.

5. Harlequin Rasboras (Trigonostigma Heteromorpha)

The intermediate care level fish is another to consider for a small tank to avoid overstocking it. 

Their maximum size can reach up to two inches and their lifespan up to three years when cared for properly.

They suit a small tank because they are peaceful and can harmoniously live with other fish in a community tank. 

Take note that they have an omnivore diet.

Keep them in a well-planted tank and make them happy.

Choose from colors like golden, rosy red, or copper and add a pop of color in your tank.

6. Honey Gourami (Trichogaster Chuna)

If you’re a beginner looking for an easy to care for fish, the honey gourami is one of your best bets. 

This fish is related to the dwarf gourami and initially might look silvery and bland until they become familiar with the tank. They can be kept in pairs in a small tank.

They require temperate and freshwater conditions, can live between four to six years, and grow up to two inches. 

Once settled in the tank, their color changes and becomes golden honey, which makes them more beautiful.

7. Guppy (Poecilia Reticulate)

Guppy is a cute and peaceful fish that you can keep in a 5-gallon nano tank.

They come from the tropical waters of South America and have been a favorite among fishkeeping enthusiasts.

In addition, they are available in a wide range of colors to choose from, adding life to any aquarium. 

They’re also easy to breed, so they can fill your tank quickly, too. You might want to stick with male guppies to avoid overcrowding your 5-gallon tank. 

They’re also easy to care for and require tropical and freshwater conditions. They can live for up to two years at optimal conditions.

8. Cherry Shrimp (Neocaridina Davidi)

The shrimp can grow up to 1.5 inch and live up to two years. They’re peaceful and require an omnivore diet.

Also, they do need to be kept in freshwater tropical water conditions.

Like the Nerite snail, they do graze on the algae in the surface of the tank, so they can help clean the decoration and glass.

They also love it in well-planted tanks with lots of sheltered spots and hiding places.

Cherry Shrimp is a popular type of hardy shrimp in the fishkeeping world and is available in red color. You will also find them in a wide range of shades. Depending on the coloration’s depth, they’re graded.

9. Least Killifish (Heterandria Formosa)

The fish is relatively hard to find in a local aquarium store, but they can be bought from online retailers at an affordable price.  

Their care level is for beginners, so you can consider them if it’s your first time stocking a tank. 

You’ll love their peaceful temperament, making them an ideal choice for a community tank.

They can be happier when kept in a tank with a lot of plants and hiding places.

However, they do have a few requirements like an omnivore diet and tropical and freshwater conditions. 

They can live between three to four years and can grow from 1 to 1.4 inches in length.

Take note, though. They’re shoaling fish, so they’re happier when with a group of their own in the tank.

Having this said, you might not have more room for other species if you choose this fish.

10. Celestial Pearl Danios (Danio Margaritatus)

This fish is not for beginners, but they’re also suitable for a small 5-gallon tank, as they can grow up to one inch only.

They can live between three and five years, have an omnivore diet, and require a tropical water condition.

They have a peaceful and lively personality, making great additions to a small tank. You’ll also love their curious personality and lovely appearance, adding more life to your tank. 

Celestial pearl danios work well in a community tank, but they should be with their own kind to keep them happy. 

11. White Cloud Mountain Minnow (Trigonostigma Heteromorpha)

This is a beginner fish with a peaceful temperament. They’re relatively easy to care for, so beginners can find delight in taking care of them.

In addition, they have an omnivore diet and require a temperate freshwater condition.

The temperature desired is around 60 degrees Fahrenheit. They’re not suitable for a tropical tank.

These lovely pets can grow up to one and a half inches and live between three to five years.

If you’d select the white cloud mountain minnow, remember that the shoaling fish finds it more enjoyable to live with a group of the same species.  

12. Clown Killifish (Aplocheilus Annulatus)

The Clown Killifish is easy to care for, so beginners won’t have a hard time keeping them. They have a peaceful temperament and require tropical and freshwater water conditions. 

Their lifespan is between three to five years and their maximum length is one inch.

The fish is attractive and can add more life to your tank. While they can be kept in a 5-gallon tank, they’d love it when they can swim in a much larger space. They also prefer to live in a well-planted tank.

They have a peaceful temperament and require an omnivore diet.

However, they’re quite sensitive and need well-filtered water.

High water circulation rates are also important aside from a filtration system. Otherwise, they can become easily stressed when kept in a tank with poor water conditions.

13. Rosy Loach (Tuberoschistura Arakanensis)

The freshwater fish has a peaceful temperament and an easy care level. They have an omnivore diet and can live up to five years. Their maximum size can reach only one inch.

They are active and highly-sociable, enjoying their company in the tank. However, they do need to be kept in a group for them to be happy.

They require gentle and slow water movement and would love a tank with dense planting and more hiding places. 

However, they need sandy and soft substrate because their sensory barbells are quite delicate and can easily be damaged.

14. Nerite Snail (Neritidae)

The snail has a peaceful temperament and is easy to care for.  They do need an omnivore diet, so giving them a combination of foods would be helpful.

The freshwater tropical creature can grow to one inch and live up to two years. They are available in a wide range of colors, making lovely additions to your small tank.  

These mollusks graze and feed on algae on the surface of and decorations in the tank, making them helpful for a small tank. They can live well with other invertebrates and fishes.

15. Dwarf Puffer (Carinotetraodon Travancoricus)

The dwarf puffer is suitable for a small tank, but they shouldn’t be kept with peaceful fish. They have an aggressive temperament and a carnivore diet.

Their care level is intermediate, they require tropical and brackish/freshwater conditions, and their lifespan is up to 10 years.

This pea-sized fish is intelligent and active, making any tank lively.  They have a distinct pattern that makes them interesting to watch.

Initially, these cute fishes are shy, but they’ll quickly adapt and notice you, as they become more familiar in their new surroundings.

4 Fishes Unsuitable For A 5-Gallon Tank

If there are fish species to keep in a small tank, you should also know what species are not suitable for it. I’ve listed the top no-nos in the following.

1. Goldfish (Carassius Auratus)

While your kids would love them, they’re not suitable for a small tank. They can grow fast from two inches to six inches and even larger for some varieties.

Living alone can also prove to be very stressful for them because they’re sociable and would love company.

Goldfish can be messy in a tank. They can produce a lot of waste that can disturb the order in the aquarium.

In addition, this fish species tends to dig at the tank’s substrate, causing more pollution. Nevertheless, a goldfish is a biological overload in a small tank.

2. Angelfish (Pterophyllum)

This tropical fish has attractive colors and can move gracefully, so they’re a favorite among fishkeepers.

While they’re beautiful and stunning, they’re not recommended for small tanks because they can grow large.

They may start small at 1.5 inches, but they can grow up to at least six inches, as they mature.

Angelfish won’t do well in a small tank. They don’t only grow large for it, but they also tend to nip tank mates.

They can also be aggressive towards smaller fishes. And as they are territorial, they tend to pick fights and cause stress to other fish.

3. Cichlids

They are territorial fish species, so they are not suitable for a small tank with other fishes. They can also feed on invertebrates and smaller fishes. Plus, cichlids are happier when kept in a larger tank.

4. Pygmy Fish

You should not keep this fish in a 5-gallon tank because it is sensitive to water parameter changes. A population of this fish can easily be wiped out when the parameters go imbalanced.

Stocking Combinations For A 5-Gallon Tank

Fish are individuals with different temperaments, so it is important to consider their personalities and behaviors when pairing them with other fishes.

Even if you have a small tank, you still need to consider a good compatibility among your pet fish. In the following are some suggestions of stocking combinations you may want to consider.

Combination #1

  • Three females and one male celestial pearl danios
  • Two cherry shrimps

Combination #2

  • Two cherry shrimps
  • One betta

Combination #3

  • Two Thai micro crabs
  • Five cherry shrimps

What Are The Best Plants For A 5 Gallon Tank?

Aside from answering the question of how many fish in a 5 gallon tank when stocking your aquarium, you must also consider the type of live plants that will do well in this small setup. 

Live plants are a great idea for maintaining water quality and balance in the tank.

Adding and setting up a well-planted tank will also help to keep the fish happy.

They can also provide hiding and resting places for shy fishes and offer them ways of exploring their new surroundings.

Even adding some live plants in the aquarium can help maintain the water parameters.

However, you might be worried or even intimidated by the thought of putting plants in the tank.

The following are a couple of suggestions for less demanding live plants to add to a 5-gallon tank. These plants don’t need expert care and specialty lighting as well as fertilizers.

  • Marimo Moss Balls
  • Java Fern
  • Anubias
  • Brazilian Micro Sword
  • Java Moss

Things To Consider For A 5 Gallon Fish Tank

Besides the types of fish and plants to set up in the tank, you must pay careful attention to certain things when stocking it.

Heater And Filtration

All tanks need a filtration system regardless of the tank size. A heater will also be needed if you’re keeping tropical freshwater species.

They can help maintain the cleanliness and water quality as well as keep the right temperatures based on your fish’s requirements.

Behavior And Size

You must take the fish behavior and size into consideration when setting up the tank as well as figuring how many fish in a 5 gallon tank.

For instance, fish can grow quickly, and others are shoaling fishes that can be stressed easily when alone or not kept in groups of at least six fishes of their kind.

Some species can also be aggressive and territorial and can find happiness in a tank when they’re alone rather than being community members.

There are also fishes that need a lot of swimming space because they are energetic and active; thus, a small tank can be stressful for them.

Nevertheless, do your homework before buying fish to add in a small aquarium, ensuring their behavior and size will suit it.

Shape Of The Tank

It will be a better idea to choose a long and rectangular tank than a hexagonal, tall, cube-shaped, or square tank because it is easier to decorate and stock.

I won’t also recommend a vase or a fish bowl because any of these will have a limited surface area and space.

There will be a low level of dissolved oxygen, which can spell disaster and even be fatal to any creature living in the tank.

Frequently Asked Questions

What Fish Fits In A 5 Gallon Tank?

Mollies, bettas, honey gouramis, and guppies are some suitable fishes for a small tank. You can refer to the previous sections for more choices.

Can You Mix Fish In A 5 Gallon Tank?

Yes, you can. Refer to the previous sections for suggested combos.  Ideally, some small fishes and invertebrates, such as shrimps and snails will do well in a small aquarium.

Can Guppies Live In A 5 Gallon Tank?

Yes, they can. You can consider a group of four or five male guppies or five inches worth of guppies. In a small tank, you can also add two females and one male. To keep it simple, one male and one female may be enough, though.

What Can Live With A Betta In A 5 Gallon Tank?

Bettas can live with other fishes, such as Dwarf Rasboras, Ramshorn Snails, Least Killifish, Chili Rasboras, Phoenix Rasboras, Strawberry Rasboras, and Celestial Pearl Danio.

Can 2 Female Bettas Live In A 5 Gallon Tank?

Yes, two female bettas can live peacefully in a five-gallon tank.

If you want to add more tank mates, you should add more space.

For example, a group composed of four to six female bettas will need a 10-gallon tank.

However, some sources claim not to keep more than one betta fish in this tank size because it can cause stress that may shorten their lifespan.

Final Thoughts

We hope you are enlightened on the topic “how many fish in a 5 gallon tank” after reading this post.

Again, the number of fish to keep in a tank this size depends on certain factors like the size and behavior of the fish. But as a general rule, it should be five inches worth of fish for a tank this size.

Besides the number of fishes, though, consider the heater, filtration and tank shape as well as overall decoration and live plants to add in it.

Take your time and do your homework. Soon enough, you’ll set up an underwater paradise regardless of the tank’s small size.


Passionate fishkeeper. Nature lover. Creative thinker. Music junkie. Adventurer.

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