Best Fish for A 3 Gallon Aquarium [List of 9 Best]

Looking to add life and color to your small aquarium? 

In this guide, we’ll explore the world of fishkeeping and help you discover the best fish for a 3-gallon aquarium. 

Whether you’re a beginner or a seasoned hobbyist, finding the right fish for your small tank can make all the difference in creating a thriving aquatic ecosystem. 

Join us as we dive into the top choices for stocking your 3-gallon aquarium with vibrant and fascinating fish species.

1. Betta Fish (Betta Splendens)

Bettas are a popular choice for small aquariums due to their vibrant colors and labyrinth organ, which allows them to breathe air from the water’s surface. They should be kept alone or with peaceful tank mates due to their territorial nature.

Why Betta Fish (Betta Splendens) is the Perfect Choice

Beautiful and Colorful:

Betta fish come in a variety of vibrant colors and striking fin shapes, making them visually appealing additions to any aquarium.

Ideal for Small Tanks:

Bettas are well-suited for small aquariums like 3-gallon setups due to their small size and ability to breathe air from the water’s surface using their labyrinth organ.

Low Maintenance:

They require minimal maintenance compared to some other fish species. Regular water changes and a well-filtered tank are usually sufficient to keep them healthy.

Solitary Nature:

Bettas prefer to live alone, so they don’t require companionship from other fish. This makes them ideal for a small tank where space is limited.

Unique Personalities:

Despite their solitary nature, bettas have unique personalities and can interact with their owners. Some bettas even recognize their owners and may respond to them.

Affordable and Accessible:

Betta fish are readily available in pet stores and are usually affordable, making them accessible to beginner fish keepers on a budget.

Hardy and Resilient:

Bettas are hardy fish that can tolerate a range of water conditions. This makes them suitable for beginners who are still learning the ins and outs of aquarium maintenance.

Lively Swimmers:

Despite their reputation for being slow-moving, bettas are actually quite active swimmers, especially when provided with ample space and enrichment in their environment.

2. Dwarf Rasbora (Boraras spp.)

Dwarf rasboras, such as the Chili Rasbora (Boraras brigittae), are small, peaceful fish that do well in small aquariums. They thrive in schools and add lively movement to the tank.

Why Dwarf Rasbora (Boraras spp.) is the Perfect Choice

Small and Peaceful:

Dwarf rasboras are tiny fish that are peaceful and well-suited for small aquariums like 3-gallon tanks.

Schooling Behavior:

They thrive when kept in groups, adding lively movement and activity to the aquarium.

Colorful Addition:

Dwarf rasboras come in various colors, including vibrant reds and oranges, adding visual interest to the tank.

Low Maintenance:

They have minimal care requirements, needing only regular water changes and a well-filtered tank to thrive.

Community-Friendly:

Dwarf rasboras are compatible with many other peaceful fish species, making them suitable for community tanks with small inhabitants.

Hardy and Resilient:

They are hardy fish that can adapt to a range of water conditions, making them suitable for beginner fish keepers.

Active Swimmers:

Despite their small size, dwarf rasboras are active swimmers, exploring every corner of the aquarium and engaging in natural behaviors.

Budget-Friendly:

They are usually affordable and readily available in pet stores, making them accessible to a wide range of fish keepers.

3. Celestial Pearl Danio (Celestichthys Margaritatus)

Also known as the Galaxy Rasbora or Microrasbora, this small fish is ideal for nano aquariums. They are peaceful and prefer to be kept in groups.

Why Celestial Pearl Danio (Celestichthys Margaritatus) is the Perfect Choice

Stunning Appearance:

Celestial Pearl Danios are known for their striking appearance, with iridescent blue and orange colors that stand out in any aquarium.

Small Size:

They are tiny fish, making them perfect for small aquariums like 3-gallon tanks where space is limited.

Peaceful Nature:

Celestial Pearl Danios are peaceful fish that get along well with other small, non-aggressive species, making them suitable for community tanks.

Active Swimmers:

Despite their small size, they are active swimmers, adding movement and liveliness to the aquarium.

Shoaling Behavior:

They thrive when kept in groups, forming shoals that move together throughout the tank.

Low Maintenance:

These fish have minimal care requirements, needing only regular water changes and a well-filtered tank to thrive.

Unique Behavior:

Celestial Pearl Danios exhibit interesting behaviors, such as darting around the tank and exploring their surroundings.

Hardy and Resilient:

They are hardy fish that can tolerate a range of water conditions, making them suitable for beginner fish keepers.

4. Endler’s Livebearer (Poecilia Wingei)

Endler’s Livebearers are small, colorful fish that are closely related to guppies. They are active swimmers and do well in small aquariums, but make sure to provide hiding spots for them.

Why Endler’s Livebearer (Poecilia Wingei) is the Perfect Choice

Colorful and Vibrant:

Endler’s Livebearers come in a variety of bright colors and patterns, making them visually appealing additions to any aquarium.

Small Size:

They are small fish, perfect for small aquariums like 3-gallon tanks, where space is limited.

Active Swimmers:

Endler’s Livebearers are active swimmers, adding movement and energy to the tank.

Peaceful Nature:

They are peaceful fish that get along well with other small, non-aggressive species, making them suitable for community tanks.

Hardy and Resilient:

These fish are hardy and can tolerate a range of water conditions, making them suitable for beginner fish keepers.

Low Maintenance:

Endler’s Livebearers have minimal care requirements, needing only regular water changes and a well-filtered tank to thrive.

Livebearer Reproduction:

They are livebearers, meaning they give birth to live young, which can add interest to the tank as the fry grow.

Affordable and Accessible:

Endler’s Livebearers are usually affordable and readily available in pet stores, making them accessible to a wide range of fish keepers.

5. Shrimp (Neocaridina and Caridina Species)

Many species of freshwater shrimp, such as Cherry Shrimp (Neocaridina davidi) and Crystal Shrimp (Caridina cantonensis), are suitable for small aquariums. They are excellent algae eaters and add interest to the tank with their behavior and coloration.

Why Shrimp (Neocaridina and Caridina species) are the Perfect Choice

Natural Cleaners:

Shrimp are excellent algae eaters, helping to keep the aquarium clean and balanced.

Small Size:

They are tiny creatures, perfect for small aquariums like 3-gallon tanks, where space is limited.

Peaceful Inhabitants:

Shrimp are peaceful and get along well with other tank mates, making them suitable for community tanks.

Varied Colors:

Neocaridina and Caridina species come in a range of vibrant colors, adding visual interest to the tank.

Low Maintenance:

Shrimp have minimal care requirements, needing only regular water changes and a well-filtered tank to thrive.

Unique Behaviors:

They exhibit interesting behaviors such as grazing on surfaces and interacting with their environment.

Safe with Plants:

Shrimp are plant-safe and won’t harm live plants, making them a great addition to planted aquariums.

Breeding Potential:

Shrimp can breed prolifically in the right conditions, providing the opportunity for a self-sustaining colony in the aquarium.

6. Pygmy Corydoras (Corydoras Pygmaeus)

Pygmy Corydoras are tiny catfish species that do well in small aquariums. They are peaceful and should be kept in groups. They help keep the substrate clean by sifting through it for food.

Why Pygmy Corydoras (Corydoras Pygmaeus) are the Perfect Choice

Tiny and Cute:

Pygmy Corydoras are small, adorable fish that add charm to any aquarium, especially smaller ones like 3-gallon tanks.

Peaceful Nature:

They are peaceful and get along well with other small, non-aggressive fish, making them suitable for community tanks.

Bottom Dwellers:

Pygmy Corydoras are bottom dwellers, actively scavenging for food and keeping the substrate clean.

Schooling Behavior:

They thrive when kept in groups, forming schools that add movement and activity to the tank.

Hardy and Resilient:

These fish are hardy and can tolerate a range of water conditions, making them suitable for beginner fish keepers.

Low Maintenance:

Pygmy Corydoras have minimal care requirements, needing only regular water changes and a well-filtered tank to thrive.

Compatibility with Plants:

They are plant-safe and won’t harm live plants, making them a great addition to planted aquariums.

Unique Appearance:

Despite their small size, Pygmy Corydoras have unique patterns and markings that make them stand out in the tank.

7. White Cloud Mountain Minnow (Tanichthys albonubes)

These small, peaceful fish are suitable for small aquariums and can tolerate a wide range of water conditions. They do well in groups and add activity to the tank.

Why White Cloud Mountain Minnow (Tanichthys Albonubes) is the Perfect Choice

Hardy and Resilient:

White Cloud Mountain Minnows are hardy fish that can tolerate a wide range of water conditions, making them ideal for beginner fish keepers.

Small Size:

They are small fish, perfectly suited for small aquariums like 3-gallon tanks, where space is limited.

Peaceful Nature:

These minnows are peaceful and get along well with other small, non-aggressive fish, making them suitable for community tanks.

Active Swimmers:

White Cloud Mountain Minnows are active swimmers, adding movement and liveliness to the aquarium.

Cold Water Fish:

They prefer cooler water temperatures, which makes them suitable for tanks without a heater, saving on equipment costs.

Low Maintenance:

These fish have minimal care requirements, needing only regular water changes and a well-filtered tank to thrive.

Breeding Potential:

White Cloud Mountain Minnows are prolific breeders, providing the opportunity for a self-sustaining colony in the aquarium.

Schooling Behavior:

They thrive when kept in groups, forming schools that create a visually appealing display in the tank.

8. Scarlet Badis (Dario Dario)

Scarlet Badis are small, colorful fish with interesting behaviors. They prefer heavily planted aquariums with plenty of hiding spots. They can be kept in small groups but should not be housed with aggressive tank mates.

Why Scarlet Badis (Dario Dario) is the Perfect Choice

Stunning Colors:

Scarlet Badis are known for their vibrant red and blue colors, making them visually striking additions to any aquarium.

Small Size:

They are tiny fish, perfect for small aquariums like 3-gallon tanks, where space is limited.

Peaceful Nature:

Scarlet Badis are peaceful and prefer to live in calm, well-planted aquariums with other small, non-aggressive fish.

Unique Behaviors:

They exhibit interesting behaviors, such as hiding among plants and darting out to catch small prey.

Low Maintenance:

These fish have minimal care requirements, needing only regular water changes and a well-filtered tank to thrive.

Suitable for Planted Tanks:

Scarlet Badis are compatible with planted tanks, providing natural hiding spots and visual interest.

Hardy and Resilient:

They are hardy fish that can adapt to a range of water conditions, making them suitable for beginner fish keepers.

Eye-catching Display:

Despite their small size, Scarlet Badis create a captivating display in the aquarium with their vibrant colors and unique behaviors.

9. Guppies (Poecilia Reticulata)

While guppies are more active and may prefer larger tanks, they can be kept in a well-maintained 3-gallon aquarium. They are colorful and come in various tail shapes and patterns.

Why Guppies (Poecilia Reticulata) are the Perfect Choice

Colorful and Varied:

Guppies come in a wide range of vibrant colors and patterns, making them visually appealing additions to any aquarium.

Small Size:

They are small fish, making them suitable for small aquariums like 3-gallon tanks, where space is limited.

Active Swimmers:

Guppies are active swimmers, adding movement and liveliness to the tank.

Peaceful Nature:

They are peaceful fish that get along well with other small, non-aggressive species, making them suitable for community tanks.

Easy to Breed:

Guppies are prolific breeders, providing the opportunity for a self-sustaining colony in the aquarium.

Low Maintenance:

These fish have minimal care requirements, needing only regular water changes and a well-filtered tank to thrive.

Suitable for Beginners:

Guppies are hardy fish that can tolerate a range of water conditions, making them ideal for beginner fish keepers.

Educational Value:

They provide an excellent opportunity for observing the breeding process and the development of fry, making them educational for fish keepers of all ages.