What Are the Best Fish for a 3-Gallon Tank (12 Best Fish)

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Best Fish for a 3-Gallon Tank

Here are the top ten best fish for a three-gallon tank. While three gallons isn’t very big, plenty of aquatic creatures can thrive in a tank of this size. So even if your favorite breed isn’t suitable for a three-gallon tank, there’s likely an alternative on this list that you’ll love. 

You’ll find a list of stocking ideas, fish to avoid, what you should consider before you buy a tank, and a few other helpful tips.

Tip: While these fish are small, you should still avoid crowding too many in one tank. Your fish need plenty of places to hide and explore. To give your new pets the best quality of life in their three-gallon tank, you’ll want to provide some plants, rocks, and other tank decorations. 


1. Betta Fish

Also known as “Siamese fighting fish,” bettas are an excellent choice for your three-gallon fish tank. They can come in various vibrant colors, and the males have beautiful, flowing tails. 

Bear in mind that these fish are not low maintenance. They are a tropical species, so their tank will require a water heater. They also have high-protein dietary needs that may differ from other fish living in their tank. 

You should also avoid putting two male bettas together, as they can be pretty violent and will end up fighting. On the other hand, female bettas can usually live together without conflict. 

2. Endler Guppies 

Endler guppies are the best fish for a small bowl. They don’t need very much space at only one inch long so that they can thrive in a three-gallon bowl for several years. 

Those looking for a colorful aquatic pet will love the Endler guppy. Their vibrant orange stripes are sure to catch anyone’s eye. 

3. Sparkling Gourami 

Often known as the “Pygmy Gourami,” these elegant fish genuinely live up to their name. The vibrant blue scales covering their bodies make them look nothing short of a glittery disco ball. 

The sparkling gourami can grow around 1.5 inches, making a three-gallon tank suitable for these fish. 

4. Ember Tetras 

If you’re looking for a splash of color in your fish tank, this fish is the way to go. Its vibrant orange scales are simply beautiful! 

They look pretty similar to goldfish, which you can’t keep in a three-gallon tank, so the ember tetra makes a great alternative. The ember tetra can grow up to one inch long as an adult. 

5. Zebra Danios

The low-maintenance zebra danios can happily thrive in a three-gallon fish tank at roughly one and a half inches long. 

Not only does it get along well with other types of fish, but it’s simply beautiful. As its name suggests, its dark blue and white stripes appear similar to a zebra’s stripes. 

6. White Cloud Minnows 

The white cloud minnow is the easiest fish to care for in a bowl. They make a wonderful low-maintenance pet for beginners. A fully-grown white cloud minnow can grow up to one and a half inches long. 

Despite their name, these fish are pretty colorful. They have vibrant blue stripes on the sides of their bodies and some patches of deep pink on their tails and fins. 

7. Pygmy Corydoras 

An adult pygmy corydoras is no more than one inch in length. With their calm temperaments and low maintenance, they can pair wonderfully with the other fish in your three-gallon tank. 

They may not be as colorful as some of the other fish on this list, but their black and silver scales are still beautiful all the same. 

8. Pea Pufferfish 

If you’re looking for a unique fish for your three-gallon tank, the pea pufferfish is the way to go. At their largest, these fish can grow up to one and a half inches. 

They have a slightly aggressive temperament, but they can get along well with other fish if they have enough space. Ember tetras and shrimp are the most suitable candidates when searching for a pufferfish companion. 

9. Six-Ray Corydoras

An adult six-ray corydoras is just a little over one inch long. It has black and white speckled scales and two whisker-like appendages on its face. Its appearance is somewhat similar to that of a catfish. 

These adorable fish are great for beginners. Because they like to feed on algae, they can also help keep the tank clean. 

10. Scarlet Badis 

The scarlet badis, or the gem badis, is one of the smaller options on this list. Adult males are just over half an inch in length.

The males have vibrant orange and white stripes similar to a clownfish’s pattern. On the other hand, the females have a more muted color scheme but are still beautiful all the same. 

11. Snails 

While they aren’t technically fish, snails can easily thrive in a three-gallon fish tank. In addition, these adorable mollusks are very low maintenance, so they’re great for beginners. 

Whether you opt for land snails or aquatic snails, there are many unique types to choose from. Just make sure you choose a smaller breed, preferably under two inches. 

12. Shrimp 

Believe it or not, freshwater shrimp can make excellent pets! Cherry shrimp and ghost shrimp are the best species to keep in tanks, as they have a reputation for being quite hardy. 

However, you will want to avoid pairing them with carnivorous or omnivorous fish, as they are often a common source of prey.

Types of Fish That Should Not Be Kept in a 3-Gallon Tank.

While a three-gallon tank is convenient, it’s not an appropriate size for most aquatic pets. Here are a few common fish that you should not try to keep in a three-gallon tank. 


When most people think of goldfish, they often picture it in a little glass bowl—but in reality, these fish need quite a bit of space to grow and thrive. 

If you’re considering buying a pet goldfish, you’ll need a tank that holds a minimum of twenty gallons. 


While sparkling gourami can thrive in a three-gallon tank, standard gourami cannot. These fish can grow quite large, some reaching up to six inches in length. As a result, they require a ten-gallon tank or larger. 


Cichlids can grow quite large, some reaching up to fourteen inches in length! So to ensure your cichlid has plenty of room to swim and thrive, a three-gallon tank isn’t sufficient; they’ll need at least a thirty-gallon tank. 

What Kind of Fish Can You Keep in a 3-Gallon Tank? 

The fish we’ve featured on this list are just a handful of suitable options for your three-gallon tank. If there’s a different species you’d like to consider, you should make sure they fit into the three upcoming categories. 

Small Fish 

As we’ve mentioned before, three gallons is a tiny tank size. Any fish bigger than two inches will not be able to thrive in a three-gallon tank. 

On the other hand, small fish will find three gallons to be just enough—so long as they don’t have too many roommates and have plenty of tank accessories and enrichment. 

Hardy Fish 

Hardy fish are generally a result of tank breeding, and because of that, they’re much more apt to smaller spaces. 

On the other hand, wild fish are more likely to feel cramped in a three-gallon tank, regardless of how small they may be. So if you own a three-gallon tank, you’ll want to make sure you only choose hardy fish breeds. 

Cold Water Fish 

While some warm water fish can thrive in three-gallon aquariums, it’s usually in your best interest to opt for cold-water fish. Unfortunately, most tanks of this size do not come with water heaters, so keeping your tank at the proper temperature could be a little more complicated. 

It’s also worth noting that three-gallon tanks are very common among beginners. Maintaining a tank with a water heater can be more challenging for beginners. So when you opt for cold-water fish, you can generally expect them to be more beginner-friendly. 

How Many Fish Should You Keep in a 3-Gallon Tank? 

In general, it’s best to keep no more than three fish in a three-gallon tank. But depending on the size of your fish, you may be able to keep more or less. 

For every one-inch fish you own, you will need at least one gallon of space in the tank. So if you come across fish species that are well under one inch long, you may be able to keep four of them in a three-gallon tank. 

And if you have a fish that’s more than one inch in length, you should probably keep only one or two in your three-gallon tank. 

Keeping Fish in a 3-Gallon Tank – What You Need to Know 

Sufficient tank space and suitable tankmates aren’t the only factors to consider when raising fish. To give your pet fish healthy, fulfilling lives, you will need plenty of equipment and time. In addition, even low-maintenance fish need plenty of care! 

Equipment You Need 

If your three-gallon tank has a tropical fish like a betta, you’ll need to invest in a water heater to keep their tank at the appropriate climate. If the water in their tank is too cold, they will become ill and eventually die. 

Keeping your fish tank clean is also crucial for your aquarium’s health. Illness-causing bacteria can quickly build up in fish tanks, harmful to you and your pets. 

To ensure that your fish live in a clean environment, you should install a water filter. This helps remove bacteria, ammonia, and other harmful substances that will accumulate in your fish tank. 

A water conditioner is also essential, especially if you have betta fish. A conditioner can help control the number of good bacteria in your fish’s water. It can also eliminate chlorine or other chemicals that are often in your tap water, which can be harmful to your fish. 

You will also want to have a substrate (such as pebbles or sand) lining the bottom of your fish tank. This is important for maintaining good bacteria in the environment. It’s also necessary to grow some aquatic plants for your fish to enjoy. 

Finally, it’s essential to have plenty of decor and other sources of enrichment. Not only do they look pretty, but these can give your fish plenty of places to hide when they need to feel secure. 

How Often to Change the Water 

Even with a filter and plenty of water conditioner, it’s essential to change your tank’s water reasonably often. A clean environment is necessary for your fish to thrive since harmful bacteria and ammonia can build up pretty quickly. 

You should refresh the water in your three-gallon tank once per week. Remember: you should only change half of the water at a time. Too drastic of a water change could potentially shock your fish. 

Beautiful 3-Gallon Tank Ideas and Stocking Options? 

Still not sure which fish to get? Here are a few fish stocking options to consider. These combinations not only have compatible temperaments, but they will look beautiful together in your fish tank. 

  • Bettas + ember tetras. These two fish have vibrant colors that can pair together wonderfully. They also have compatible temperaments, so you can expect them to get along just fine. 
  • Ember tetras + shrimp. With the vibrant colors of the ember tetra, and the calm tempered and colorful shrimp, these creatures can make a unique stocking combo for your three-gallon tank. 
  • Snails + shrimp. If you want some sea creatures that aren’t fish, this unconventional combo is the way to go. Most species of snails will get along just fine with shrimp. In addition, both of these creatures are pretty low maintenance, making them great for beginners. 
  • Zebra danios + sixray corydoras. These two fish have compatible temperaments and have similar black-and-white color schemes. They look simply beautiful together! 

What Aquarium Plants Can You Add to a 3-Gallon Tank?

Adding plants to your aquarium is a great way to provide enrichment and hiding places for your fish. In addition, the right aquatic plants can make your tank look all the more beautiful. 

For instance, a waterwheel plant has a wheel-like structure that is notably eye-catching. And the rotala rotundifolia or rotala indica both have a pretty sunset-pink hue. 

Or, if you’re looking for something simple, we suggest planting some Sagittaria, java moss, anubias, or java ferns. 

Here are a few other live plants that would work well in a three-gallon tank:

  • Vallisneria
  • Green Hygrophila
  • Moneywort
  • Sunset Hygro
  • Hornwort

Our Recommendation for the Best Fish to Keep in a 3-Gallon Tank?

Perhaps, the easiest fish to take care of in a 3 gallon tank is White Cloud Minnows. It’s small (grows up to a maximum of 1.5 inches) and hardier than most small schooling fish, and can withstand most of the mistakes by novice fish caretakers. The only exception is copper medication.

Our Recommendation for a Great 3-Gallon Fish Tank


What fish can live in a 3-gallon tank?

You can keep various fish and other aquatic animals in a three-gallon tank, including betta fish, Endler guppies, and even shrimp. 

Fish that are small, hardy, and can live in cold water are best for three-gallon tanks. But, of course, there are some exceptions, such as the tropical betta fish. 

However, it’s best to avoid keeping larger fish in tanks of this size. This includes goldfish; while they start small, they can grow quite big when they live in an appropriate-sized tank. 

So when you keep a goldfish or other larger fish in a three-gallon tank, you will end up stunting their growth and impacting their quality of life. 

How many fish should you put in a 3-gallon tank?

You can keep up to three tiny fish in a three-gallon tank. You need one gallon of water for every one-inch fish in the tank, so make sure these fish are no larger than an inch. You’ll want to stick with one or two instead if they are. 

How many neon tetras can I put in a 3-gallon tank? 

You can keep between two and three neon tetras in a three-gallon tank. Because these fish are so small, a tank of this size should be sufficient for them to live comfortably. 

Before you go check out our list of popular aquarium fish you can use in your next tank.



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