The Best Fish For 3 Gallon Tank

In this article, we discuss the best fish for a 3-gallon tank, focusing on small and compatible species. Featured species include Guppies, Endler’s Livebearers, Cherry Shrimp, Ember Tetras, Chili Rasboras, Zebra Danios, White Cloud Mountain Minnows, and Otocinclus.

Tips on maintaining a healthy nano aquarium are provided, emphasizing regular water changes and filter maintenance. Our aims is to assist readers in creating a vibrant, sustainable small aquarium environment.

Fishkeeping has become a common hobby, but people don’t want to take care of a big tank. Thus, they are shifting towards nano tanks, like 3 gallons tanks. The reason being less cleaning and maintaining effort required by smaller tanks. 

A small aquarium can be easily cleaned as compared to a 100 gallons fish tank. And there are several attractive fish available that one can keep in a nano 3 gallons tank. 

As the options are multiple, picking one is not possible. But Guppies are our absolute favorite. This small-sized fish looks adorable. Plus, they make a tank lively with their colorful presence. They don’t have demanding maintenance requirements. 

Other than guppies, we have also suggested some more fish species that can be easily kept in a 3 gallons tank. You can go through their requirements and characteristics to know them in a better way. 

List of Fish for 3 Gallons Tank 

When housing a fish in a 3 gallons tank, one thing to consider is its size. If the fish can grow to a bigger size, you must avoid keeping it. That’s because then they won’t get enough space to swim and they will not live happily. 

So, after digging the internet, we have listed some beautiful fish species that you can house in your small tank without any hassle. Scroll down to know about them. 

#1 Guppies


Guppies are a popular choice for keeping in a 3 gallons aquarium both by beginners and experts. The vibrant color and playful energy of a Guppy are what attracts tank keepers. Not to mention, this fish species is easy to take care of. 

These are friendly creatures, making them a perfect choice for keeping with any other smaller-sized fish. Try not to keep Guppy with any fish that is bigger because then Guppies might become a snack. 

A thing to note about this fish species is that it reproduces frequently. If you don’t want your tank to get filled by several small baby guppies, try keeping males and females in separate tanks. 

Scientific name Poecilia reticulata
Size 1.2 – 1.5 inches 
Tank setup A heater and enough place to swim
Tankmates Other small and sociable fish

If you don’t want your fish to get sad, always keep it with a compatible tankmate. 

#2 Endler’s Livebearers 

Endler's Livebearers

Endler’s Livebearers are often called Guppy cousins because they are also smaller in size. And just like Guppy, these come in vibrant colors, making them so popular among tank keepers. 

This fish species has a quick reproduction rate. That means it can overpopulate a 3 gallons tank if not given proper care. But you can solve this problem by keeping male and female Endler’s Livebearers in a different tank. 

To happily keep this fish species in your tank, add 4-6 fish as they don’t need a large group. If you properly feed the Endler’s Livebearers, you can keep them alive for a long time. 

Scientific name Poecilia wingei
Size 1.8 inches 
Tank setup A heater and enough place to swim
Tankmates Other small fish or you can keep 4-6 same species fish

#3 Cherry Shrimp 

Cherry Shrimp

For a change, if you don’t want to keep fish in the tank, you can consider housing adorable cherry shrimps. These are fun and come in different colors. The best thing about Cherry Shrimp is that you can house a dozen of them in a single tank. 

If the tank environment is favorable and they get everything they need, they can reproduce very quickly. While Cherry Shrimp is active, it doesn’t overpopulate the tank because of its short life span. 

Freshwater Cherry Shrimps make a great pet. With their presence, they make the fish tank visually appealing. If you keep them in a stable parameter, you can easily keep them alive. 

Scientific name Neocaridina davidi
Size 1.5 inches 
Tank setup Decent flowing current and place to swim
Tankmates They can live with a variety of fish and their kind

#4 Ember Tetras 

Ember Tetras

Another tiny fish you can house in your 3 gallons aquarium is the Ember Tetras. This fish species looks adorable, and it loves staying in school. Its bright and flashy color is hard to get unnoticed. 

Since these are extremely tiny, they live near the root of plants. Ember Tetras are sensitive fish. Thus, you must avoid keeping them with any bigger fish. 

One thing that has made this fish species so popular is its under-demanding maintenance requirement. Whether beginner or experienced, any tank keeper can house Ember Tetras without any hassle. 

Scientific name Hyphessobrycon amandae
Size 1 inches 
Tank setup Slow flowing current and driftwood 
Tankmates Guppy or any other smaller sized fish

Ember Tetras are extremely peaceful fish. Thus, you must keep them with calm fish only. 

#5 Chili Rasboras 

Chili Rasboras

While Chili Rasboras is not as popular as Guppy, it also makes an excellent 3 gallons tank member. This fish species is slowly gaining popularity for its undemanding maintenance needs and calm nature. 

Chili Rasboras is one of the smallest aquatic beings available. These are shoaling fish that need to be kept in a group of at least six. Keeping them in a group will also make your tank attractive because they come in different colors. 

To make your fish live longer, you need to adjust the water’s pH level, temperature and keep the tank clean. 

Scientific name Boraras brigittae
Size 0.7 inches 
Tank setup Live plant and enough swimming place  
Tankmates Avoid keeping it with any aggressive fish like Angelfish or Betta 

This fish species is known to be peaceful and timid. 

#6 Zebra Danios

Zebra Danios

For beginners, Zebra Danios is the perfect choice because of its low maintenance needs. With proper care, this fish species can happily survive in a 3 gallons tank. It’s a hardy fish species that need to be kept in a group of around six. 

Keeping Zebra Danios in a smaller group might make them stressed, which can further kill them. Danios come in different varieties, but this one is easy to care for. 

This fish species has a good social status that makes it one of the finest options to house other 3 gallons fish species with. Zebra Danios are not known to be aggressive. 

Scientific name Danio rerio
Size 3 inches 
Tank setup Live plant and enough swimming place  
Tankmates You can keep it with guppies, bettas, angelfish 

#7 White Cloud Mountain Minnows 

White Cloud Mountain Minnows

If you want to keep a fish that does not need a heater, White Cloud Mountain Minnows should be your pick. This shoaling fish is beginner-friendly and reproduces rapidly. If you don’t notice them, they can quickly overpopulate the 3 gallons tank. 

Keeping aside their reproduction frequency, it’s safe to say that White Cloud Mountain Minnows make an excellent aquatic pet. They are lively, they are enjoyable, and they make the tank look colorful. 

While this fish species do not need a huge aquarium to survive, it surely needs enough space for swimming. 

Scientific name Tanichthys albonubes
Size 1.5 inches 
Tank setup Enough swimming place  
Tankmates You can keep it with Zebra Danios, freshwater shrimp, and other smaller fish

#8 Otocinclus 


Next on this list is the Otocinclus, which is a tiny version of catfish. This fish species is great for controlling algae because it feeds on it. You should never house a single Otocinclus as it won’t feel safe. 

Another thing to note is that this fish is highly sociable. That means you should always keep it with other fish species. It will help Otocinclus to live happily. Also, these are known to be peaceful. So, you should always keep them with calm fish species. 

Scientific name Otocinclus
Size 1 – 1.2 inches 
Tank setup Enough swimming place  
Tankmates You can keep it with small fish and with its kind

How to Effectively Maintain a 3 Gallons Tank? 

Maintaining a 3-gallon tank involves regular water changes, frequent filter cleaning, and monitoring water parameters. It’s crucial to avoid overfeeding and maintain a stable temperature. These practices ensure a healthy habitat for small aquatic species.

Managing a 3 gallons fish tank is not tricky if you do it correctly. For the proper survival of fish, it’s advised to change 50% of the tank water twice a week. This way, harmful chemicals, and fish biodata will be removed. 

Along with changing the water, you need to clean the filter as a clogged filter won’t clean the tank water. While changing the water and cleaning the filter, you can clean the tank decoration as well. This way, your fish will get to live in a hospitable environment where you can happily grow. 


If you are a beginner, you can start your fishkeeping journey with a 3 gallons tank. That’s because this sized tank can be quickly set up. Also, the tank would not leave you exhausted with its maintenance needs. 

Among the given 3 gallons fish options, we would recommend you to have Cherry Shrimp. That’s because it will not overpopulate the tank. This further cuts down the maintenance work. 

But if you don’t want to house a shrimp, you can choose one of the options from the given suggestions. 

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