Best Fish for 3 Gallon Tank: Stocking Ideas & Tank Suggestion

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fish for 3 gallon tank

Fish can be a wonderful addition to anyone’s fish tank, but it is important to find the right fish for the right tank size. Fish are living creatures that deserve their own unique habitat that allows them to thrive and show off their personality! They also require regular care from their owners.

Before you go out and purchase the best fish for 3 gallon tank, there are some guidelines on which fish species can be kept in a 3 gallon tank and how many fishes you should have – this will allow your fish to live a long, happy life!

This guide will help many people who don’t know much about fish care because we’ll let you know what type of fish would work well with others and give a complete care guide for each of them.

How Many Fish Can I Put in a 3-Gallon Tank?

3 gallon fish tanks are small in size compared to the standard 10 gallon fish tanks. With such a small size, you are very limited in the stock you can have.

Every aquarist follows a general rule of thumb: “1 inch of fish per gallon of water”. This rule is only a generalization and shouldn’t be completely applied. Fish have different behavior patterns or care guides, and some may not obey the “1-inch” rule.

Fish for 3 Gallon Tanks stocking ideas

In general, most aquarists tend to have a single species of fish per tank since there is not enough space for more. Fish that are schooling (Tetras Guppies, etc.) will need at least 3 of their kind in order to stay happy and healthy.

Fish that can live well alone and don’t like to share their tank with others, such as Bettas, may do alright in a 3 gallon tank.

Best 3 Gallon Fish Tank: Tetra Cube 3 Gallon

Before showing you the best fish for a 3 gallon tank, it is reasonable to speak about the best 3 gallon tank you can purchase. If you already haven’t purchased one, let us suggest the best one on the market. 

Tetra Cube 3 Gallon Fish Tank Design

The Tetra Cube 3 Gallon aquarium is one of the best 3 gallon fish tanks and is the perfect solution for those looking to add an elegant and stylish fish tank to their home. Its compact design makes it easy to place on any table or desk without taking up too much room. You can even put it right next to your computer monitor so you can enjoy watching your fish while working!

The three-stage filtration system keeps water clean and clear, while the low voltage LED lighting provides a soft glow that won’t disturb your sleep. Plus with its whisper-quiet air pump, this aquarium will never make a peep! This tank will make your life easier by providing everything you need in one simple package.

Best Fish for 3 Gallon Tank

When speaking about the best fish for a 3 gallon tank, you are open to more fish species than fish that can live in a 1 gallon tank. A large variety of fish falls into this category, but the best type is small schooling fish. 

We’ll list all of them and include other fish for a 3 gallon aquarium that can be kept alone.

Neon Tetras 

Neon Tetras are colorful fish with a brilliant red line from nose to tail, followed by a sharp blue line that extends into its fins. They normally come in a school of 3 to 7. They can be kept in groups larger than that, but they should have plenty of space to swim around.

best fish for 5 gallon tank Tetra fish

For your 3 gallon tank, you can keep up to 3 Neon Tetras. If somehow you start loving them and want to stock more, consider upgrading to a 10 gallon fish tank.

Neon Tetras prefer subtropical water, with a pH between 6.0 and 7.5 and a water temperature around 75 degrees Fahrenheit. Neon Tetras can grow up to 1.5 inches, and their lifespan is around 2–3 years. This makes them the best fish for a 3 gallon tank.


Guppies are a popular choice for nano aquariums. They come in numerous colors and patterns, so there’s an option to suit every fish keeper’s tastes. Male guppies can be slightly more aggressive than females, but it varies from individual to individual.

best fish for 3 gallon tank guppies fish

You can keep 3 Guppies in your 3 gallon tank, but keep in mind that they can grow up to 4 inches (10 cm). Fish of such a size may not do well in a small tank.

Guppies prefer neutral to slightly acidic water (pH 7-8). Water conditions should be kept stable because sudden shifts can cause stress, leading to illness or even death for your fish. Guppies are tropical fish, so you will need to keep them warm – somewhere between 72-82 degrees Fahrenheit.


Betta fish is one of the best fish for a 3 gallon tank because they are cheap and easy to take care of. A Betta fish can live around 2 to 5 years if proper conditions are provided, and their size is about 2 inches long, so they won’t take up much space in a 3 gallon tank.

best fish for 3 gallon tank guppies fish

Betta fish prefer slightly acidic water with a ph of 6.5-8. A 3 gallon tank would need to have a heater since Bettas likes warm water of 75-80 degrees Fahrenheit. An aquarium filter would be essential to maintain clean water for this fish.

You can only keep only 1 Betta in a 3 gallon tank since they are aggressive toward each other. Decorating your Betta fish tank with some live plants and aquarium decoration can give your Betta more space to hide and swim around.

Cherry Shrimp

One of the best ways to stock your 3 gallon tank is by transforming it into a shrimp tank. One of the best shrimps to choose for your tank is Cherry shrimp. This species is also known as Red Cherry Shrimp or Sakura Shrimp. This shrimp has a red color with white stripes. The size of this species can reach 1 inch long but are usually 0,5 – 0,8 inches long.

best shrimp for 3 gallon tank Cherry Shrimp

Cherry shrimp’s lifespan is about 1,5 – 2 years if properly taken care of. They are an excellent choice for beginners since they don’t require much dedication, and they’re very easy to take care of. 

Cherry shrimp water temperature should be between 57–84 degrees Fahrenheit, and pH levels can range from 6 to 8. They prefer small places where they can find some dark areas for hiding, so you can add plants and aquarium decorations inside your tank.

You can keep around 6-10 Cherry shrimps, meaning that this option is your best one if you want a lot of species in your tank. Combining it with other fish for 3 gallon tank like Neon Tetras or Guppies is possible.

Chili Rasboras

Chili Rasboras is the smallest fish for your 3 gallon tank that you can get. They are easy to care for and are very peaceful. They can live up to 5 years if properly cared for and can vary in color from dark red to light orange.

best fish for 3 gallon tank chili rasbora

You need to make sure their water temperature is between 75-78 degrees Fahrenheit. The pH level should be about neutral. They are small, so you can have many of them in your 3 gallon fish tank.

Like most fish, they feed on insects, small worms, and plankton. They do great with flake food or even tubifex worms. While they are at the bottom of the tank, they will eat almost everything that falls down there.

Zebra Danio

Zebra Danios are hardy fish that is often seen in community tanks. This is due to its peaceful nature and high level of activity. Although often purchased for their beauty, they are quite useful in the aquarium as they help keep the bottom clean by eating up leftover food.

best fish for 3 gallon tank Zebra Danio

They are easy to care for when given the proper tank size and environment. You must ensure there will be enough space and hiding areas since the Zebra Fish like to stay close together. A 3 gallon tank is suitable for a group of 3-4 Zebra Fish. You can also combine it with other small fish that are suitable for a 3 gallon tank.

With a 4-5 years lifespan, the Zebra Fish can be one of the longest-living species for your aquarium. Keeping your Zebra Fish healthy will ensure they live to their full life expectancy and keep you entertained along the way! 

Least killifish

The Least Killifish is a peaceful bottom feeder that should be kept in schools of 6 or more. It has an average lifespan of 3-5 years and grows to around 1.25 inches. The temperature range for the Least Killifish is 72 – 79 degrees Fahrenheit with pH 6.0 – 7.8 and dH 5 – 19.

best fish for 3 gallon tank Least killifish

This fish is one of the best fish for 3 gallon tank because of its small size. Keeping 6 Least Killifish in your 3 gallon tank is possible as long as proper care is provided to them.

Providing bottom cover such as Dwarf Baby Tears will give them an extra sense of security and should help keep them active throughout the day. The tank must also be tightly covered because, like most livebearers, these fish are quite capable of jumping out of their tank if startled or threatened.


Otocinclus are great fish for 3 gallon tank. They are known to be hardy and peaceful, and they will not outgrow your tank. This fish may look ugly, but it’s actually cute and friendly. Fish like Otocinclus will help maintain the tank by eating algae and other leftovers that may cause problems in your aquarium. 

best fish for 3 gallon tank Otocinclus

Otocinclus lifespan is about 3 – 4 years old, but they can live a bit longer if you take good care of them. These fish have a very small body, so you should keep them in a small 3 gallon or 5 gallon fish tank with plenty of plants decor that can provide a hiding spot since they are a shy type of fish.

Ghost Shrimp

Ghost Shrimp (aka Cherry shrimp, Sakura shrimp, Glass shrimp) make the best stocking option when setting up your 3 gallon tank as a shrimp tank. Why? They are cheap and can tolerate water parameters. This makes them perfect for any fishkeepers looking to add a unique look to their 3 gallon tank while keeping the expenses low.

best fish for 3 gallon tank ghost shrimp

They are also very peaceful shrimps and get along with all fish that will fit in a 3 gallon fish tank. Furthermore, they can be kept in groups, making them one of the best 3 gallon tank stocking options if you want to keep different species.

A 3 gallon fish tank is usually sufficient for keeping up to 7 Ghost shrimps. They only grow up to 1.6-2 inches, so their footprint will not increase if you decide to add more shrimp later on.

Ghost shrimp are bottom feeders who do an excellent job at cleaning your 3 gallon tank from leftover food particles after feeding your other fish. If no other fish are present in the aquarium, they may feed on algae and biofilm growths.


Fish for 3 gallon tanks should only include small fish that will stay small even after some months into the future. Like any other aquarium, you must ensure their water parameters are within an acceptable range. However, more demanding species may need specialized equipment such as Bettas.

Even tho the 3 gallon tank is small; we provided you with enough stocking ideas to give life to your nano aquarium, from keeping only one fish, like Betta, to keeping schooling fish like Neon Tetras, Guppies, and more. Transforming your 3 gallon tank into a shrimp tank is one of the best stocking options for you.

Shrimps like Cherry Shrimp or Ghost Shrimp can be kept together with other small fish such as Least killifish, Guppies, Neon Tetras, and more. This stocking option can be considered the best one since it gives you more spices type in such a small tank.

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I am Mario, a experienced fish keepr and the editor-in-chief of Epic Aquarium.

At Epic Aquarium, we take our commitment to providing comprehensive and unbiased reviews very seriously. Our team carefully reviews each product, and we only recommend the very best in terms of quality. We also consult with leading fish keeper experts to ensure that each article is based on the most reliable and up-to-date information available.

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