Best Fish for 2 And 2.5 Gallon Tanks – Stocking Tips & More

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Stocking and caring for a smaller tank isn’t always a walk in the park. There are a lot of things to take into account, such as the size and temperament of the fish you choose. It is because of this that many seasoned fishkeepers often recommend sticking to larger tanks. However, if you know how to care for it properly, a smaller aquarium can be just as fun and rewarding.

In this article, we will discuss some tips for stocking and caring for a smaller tank, as well as some of the best fish for 2 and 2.5-gallon tanks. Hopefully, these tips will help you create and maintain a healthy and thriving small-tank ecosystem, in which your fish can thrive.

Tips For Stocking A 2 and 2.5-Gallon Tank

Before delving into the types of fish you could stock in a small tank, it’s important to first address some general tips for stocking a tank of this size. This will help to ensure that your tank is healthy and that your fish are happy and thriving.

Get Your Water Parameters Right

Male hand holding aquarium water test kit

In any tank, it’s important to ensure that your water conditions are correct before adding any fish. In a small tank, it’s even more important to get your water parameters right, as there is less water to dilute any mistakes.

A good place to start is with your pH and hardness levels. Most fish can adapt to a wide range of pH levels, but it’s always best to try and match the pH of your tank to that of the fish’s natural habitat. The same goes for hardness levels – try and replicate the water conditions in the fish’s native environment as closely as possible.

If you’re not sure what your water parameters are, you can always test them using a home aquarium testing kit. These kits are readily available at most pet stores, and they’re not too expensive.

Make Sure The Tank Is Sufficiently Heated

In the same way that your water conditions should mimic the native environment of the fish, water temperatures should be similar to that which they’re used to. While most fresh and saltwater fish can adapt to a wide range of temperatures, an aquarium’s heater is necessary for maintaining the right levels (for both temperature and pH).

A rule of thumb is to set your pre-built heaters at 78-80 degrees Fahrenheit for tropical fish, and 65-68 degrees Fahrenheit for coldwater fish. If you’re using an unheated tank, you’ll need to use a different strategy to heat your water, such as with an additional heater or by using lamps to heat the room in which the tank is kept.

There is no need for expensive heaters, as they will do nothing to increase the perceived warmth of your tank. A good heater is one that preserves heat well and does not fluctuate too much. You can find great heaters on Amazon for relatively cheap, which will do an excellent job of making cold water habitable for your fish.

Feed Your Fish Appropriately

Little girl feeding fishes in the aquarium.

Most fish don’t require a strict diet, but it’s important to remember that they still need to be fed regularly. In a small tank, it’s best to stick to a once-a-day feeding schedule, as overfeeding can lead to water quality problems.

In general, most fish will do well on a diet of fish chips or flakes, freeze-dried foods, and small pellets. It might also help to supplement their diet with live kinds of fish food, such as brine shrimp and bloodworms.

Pay Attention To Fish Size

Though the fish size isn’t the sole factor in determining their suitability for a given tank, it is something you should keep in mind when stocking a small tank. Larger fish will often outgrow a small tank, which can lead to cramped conditions and other problems.

Ideally, you should try to stick to fish that are 2 inches or less in size. This will help to ensure that your fish have enough space to swim around and avoid any potential health problems associated with insufficient space. The last thing you want to do is have to purchase antibiotic medication for a giant fish that’s living in cramped conditions.

Lighting Is Super Important!

Never underestimate the importance of lighting your tank! In a small aquarium, proper lighting conditions are crucial to ensure that plants can grow and stay healthy. This will also help with producing oxygen, as well as simulating the conditions under which most fish naturally live.

Some small tanks may come with a built-in lighting system, but you may find yourself needing to purchase separate lighting if your tank doesn’t have any. You can find a wide variety of affordable LED lights that will do the job well.

Just as important as sufficient light exposure is the type of light used. Inappropriate lighting such as metal halide or fluorescent can be harmful to both your fish and plants. It’s best to stick with LED lighting, as it provides a natural light spectrum that is ideal for aquariums.

A Good Filtration System Can Be A Lifesaver

Fish tank with filter

When it comes to small aquariums, the importance of a proper filter cannot be understated. Filter systems are designed to remove waste products from your fish, which will lead to healthier water conditions and lower odds of disease. An adequate filter system will provide your fish with a place to reproduce and hide whenever they need to, while also improving oxygenation and water clarity.

It’s best to go with a real filter chamber as opposed to an air pump and sponge filter. Air pumps are often ineffective in small aquariums, as they cannot produce enough turbulence to keep the water clean. Sponge filters also rely on organic matter to function, which can lead to unhealthy water conditions over time.

In general, a good filter for a small tank should be relatively quiet, have a turnover rate of about 4-5 times the size of the tank. This will provide your fish with excellent filtration, while also allowing you to remove waste products on a regular basis for easier upkeep.

Don’t Forget Green Aquarium Plants!

Green plants aren’t strictly necessary for a successful aquarium, but they can have several benefits. Photosynthetic plants provide your fish with a natural source of food while helping to oxygenate the tank and keep water quality high. If your small tank is looking a bit drab, additional plants might be the perfect aesthetic touch that it needs

In general, the healthy development of plants in an aquarium is a good sign, as it indicates that the water conditions are healthy and suitable for fish. If you’re having trouble getting your plants to grow, try adding a small amount of fertilizer to the water. This will help to give them a boost and get them started on the right track.

In spite of your best efforts, plants inevitably die. In these instances, it is important to remove any dead or dying plants from your tank immediately. Decaying plant matter can harm your fish and lead to water quality issues, and these adverse consequences are often amplified in a tiny tank. So if one of your plants looks like it’s struggling, don’t be afraid to say goodbye.

As you can see, stocking your tank is only half the battle! If you follow these guidelines, however, then you’ll have a beautiful aquarium filled with healthy fish that are thriving in their tiny environment. Just make sure that you’re doing regular water changes, and giving them the best possible environment to live in.

24 Fish For 2 And 2.5-Gallon Tanks

Now that we have covered the basics of small aquariums, it’s time to look at some examples of fish that will do well in them. The best candidates are species that don’t grow too large and require minimal attention to care for.

The following list gives 25 examples of well-known tropical freshwater fish species that are suitable for 2-gallon tanks. These lists should also be used as guidelines since exceptions are bound to exist. Always do your own research to ensure that a particular fish is compatible with the specific tank!

1. White Cloud Mountain Minnow

White Cloud Mountain Minnow in a black background.

The White Cloud Mountain Minnow is a small, peaceful fish that is perfect for a beginner’s tank. They grow to a maximum length of only 2 inches and can thrive in a wide range of water conditions. This makes them an ideal choice for a tank that is still in the early stages of setup, as they are very tolerant to changes in pH and temperature.

In terms of appearance, the White Cloud Mountain Minnow is a light brown fish with colorful horizontal stripes. They are naturally conditioned to live in mountain streams, so they appreciate lots of plants and areas for them to hide.

White Cloud Mountain Minnows are excellent community fish, as they are peaceful and get along well with others. This also makes them an ideal addition to fish tanks filled with more timid personalities.

2. Small Barbs Fish

Aquarium fish from genus Puntius

Barbs are a group of small, active fish that is widely available and fairly inexpensive. They come in a variety of colors and patterns, so there’s something to suit every tank! These aquatic creatures also tend to be very hardy and easy to care for, which makes them a perfect choice for beginner aquarists.

If you decide upon the checkerboard barbs or cherry barbs, then be prepared for a lively addition to your tank. These fish are constantly on the move and love to explore their surroundings. They also tend to get along well with other barbs, as well as other small fish.

3. Betta Fish

Four female betta in black background.

Bettas are probably some of the biggest fishes you can keep in a 2.5-gallon fish tank. These beautiful fishes come in a variety of colors and patterns, so there’s sure to be one that catches your eye. Bettas are also very hardy and can thrive in a range of water conditions.

However, it is important to note that Bettas are territorial fish and should not be kept in community tanks. If you’re looking for a solitary fish, then the Betta is a perfect choice. In addition, you should make sure that you do not leave your tank dirty for too long, as Bettas are very susceptible to disease. 

4. Kuhli Loach

Banded Kuhli Loach Live Fish Aquatic Pets

Loach fish is a popular choice for small fish tanks, as they are hardy and come in a variety of shapes and colors. The Kuhli Loach is no exception, as it is a small, colorful fish that is very easy to care for.

The Kuhli Loach is an active fish that loves to explore its surroundings. Its long, slender body is perfect for squeezing through tight spaces, so it’s sure to keep you on your toes. Plus, the spectacular colors on its body are sure to stand out against dark rocks and foliage.  

5. Neon Tetra

Neon tetra ( Paracheirodon innesi ) photographed in an aquarium

Often confused with the cardinal tetra, the neon tetra is a popular choice for those who want colorful fishes in their tanks. It has a body that resembles a neon light, allowing them to display an exhibit of colors that is truly amazing.

Though the blue and red neon tetras are the most popular, there are also other variants available. For example, the lemon tetra is a brilliant yellow color, and the green neon tetra is solid olive green. You may find some similarities in their behavior with neon tetras, but some of them can be more aggressive. Regardless, their bright color and small size make them a perfect choice for beginner aquarists.

6. Cory Catfish

Two small spotted Cory catfish side by side

Cats are a popular choice for small tanks, as they are hardy and come in a variety of shapes and colors. The Cory Catfish is no exception, as it is a small, colorful fish that is very easy to care for.

In fact, the Cory Catfish is so easy to care for that it can be kept in different types of water conditions. Of course, this doesn’t mean that you should house them in dirty water, but it does mean that you can create a variety of water conditions to see which one they respond best to.

7. Danios

zebra danio (stripe)
Image Source:

Danios share a lot of similarities with tetras of the same size. This includes their hardiness, peaceful temperament, and love of schooling. However, Danios tend to have a body shape that is more elongated than that of tetras. They also have a smaller body size, making them a good option for small fish tanks.

The most popular Danios are the zebra danio and the pearl danio. The zebra danio is recognizable by its dark stripes (usually black or blue stripe), while the pearl danio has a shimmering pearlescent sheen on top of its body. They are both hardy fish that can thrive in a variety of water conditions. No wonder they’re considered a favorite fish for many people!

8. Bloodfin Tetras

fish bloodfin tetra tropical aquarium

Bloodfin tetras are small, colorful fish that are native to the Amazon River basin. They get their name from the bright red coloration on their fins, which is most pronounced when they are in breeding mode.

Taking good care of blood fin tetras is easy, as they are hardy and peaceful fish. They prefer cool water temperatures between 65-75 degrees Fahrenheit, making them a good choice for those in colder climates. They are also relatively easy-going when it comes to their diet, and are happy to consume fish flakes and small live worms. 

9. Wild–Type Guppies

Female guppy endler in freshwater aquarium. Poecilia reticulata.

Exotic guppies are known for being difficult fish – at least more so than regular guppies. But what sets them apart?

Wild-type or regular guppies are the original strain of guppies that come from the wild. They are hardy and can tolerate a wide range of water conditions. They also come in a variety of colors, making them popular for aquariums. On the other hand, exotic guppies are bred to have colors and markings that are not typically seen in regular guppies, but they require specific freshwater conditions in order to thrive.

If you have a 2 or 2.5-gallon tank, the hardier wild-type guppies might be a better choice for you. This is because they are more tolerant of changes in water conditions and can survive in a wider range of habitats. Do note that they breed rapidly, so if you have pregnant female fish, you might want to consider getting a bigger tank! 

10. Swordtails

Swordtails (Xiphophorus helleri)

Fish keepers of all experience levels have kept swordtails. They are known for being friendly fish that do well in community tanks. Swordtails are also hardy and can tolerate a wide range of water conditions, though it should be noted that they tend to produce more fish waste than other smaller fish. The biggest bonus of keeping swordtails is that they are livebearers, which means they can breed in aquariums!

Swordtails come in a variety of colors and patterns, but the most common type has a silver body with blue speckles. Males also have an elongated dorsal fin known as a sword – this is how they got their name. Meanwhile, females are livebearers, which means they give birth to live fry instead of laying eggs. If you’re looking for a colorful, fun-loving fish, then consider keeping swordtails!

11. Blind Cave Tetras

Blind cave mexican tetra aquarium fish

Blind cave tetras are ideal fish for a 2-gallon tank, as they can survive in a range of water conditions. They are also interesting to keep due to the fact that they’re blind and live in caves!

This breed of tetras comes from underground caves near Monterrey, Mexico. Because they lack eyes, their other senses have become heightened. They navigate through their environment by using their lateral line, a sensory organ that runs the length of their body. This allows them to feel movement and vibrations in the water, which helps them hunt for food. 

12. Salt and Pepper Corydoras

Corydoras habrosus

Corydoras catfishes make great starter fishes in general, but the Salt and Pepper Corydoras might be one of your best bets for a 2-gallon tank. This is because they are relatively small and won’t grow to be much longer than an inch in length.

Salt and Pepper Corydoras also come from cool, fast-flowing waters – which means that they’re hardy and can tolerate a wide range of safe water conditions! Although frigid water or salty water might not be the best idea, they can thrive in most freshwater conditions.

13. Small Live Bearers

Male black-bar Endler

We’ve mentioned mollies and swordfish, but small livebearers, in general, make great additions to a 2-gallon tank. This is because they’re hardy, colorful, and easy to care for!

Endler’s livebearers are a particularly good choice as they come in a range of colors and patterns. They are also small, making them the perfect size for a 2-gallon tank.  

14. Platies

Platies (Xiphophorus maculatus)

If your aquarium pH level is stable and you’re looking for a colorful fish, then platies might be a good choice. This hardy fish comes in a variety of colors, including red, blue, yellow, and black.

One thing to note is that platies are livebearers, so you might find lots of baby platies swimming around your tank in no time! They are also relatively easy to care for, making them a good choice for beginner aquarists.

15. Black Skirt Tetra

A Black Tetra (Gymnocorymbus ternetzi) in aquarium.
Image Source:

Of the many breeds of tetras, the black skirt tetra is one of the most popular. These quiet schooling fish are very colorful and can be found with black, red, or yellow stripes. They also have a unique hanging fin that is fluffy and used for maneuvering through their home river systems in South America!

If you want a schooling fish, then the black skirt tetra is a good choice for your 2-gallon tank. They get along well with other species and are very peaceful, making them an interesting addition to your aquarium.

16. Zebra Snails

Zebra Nerite Snail
Image Source:

If you’re looking for a low-maintenance cleanup crew then zebra snails might be a good choice. These small snails are hardy and can tolerate a wide range of water conditions. They also feed on algae and uneaten food, making them beneficial to your tank.

Although they may not be the most exciting addition to your tank, zebra snails can be a helpful and low-maintenance addition to your aquarium.

17. Cherry Shrimp

Cherry Shrimp (Neocaridina davidi)

Think of cherry shrimp as aquarium creatures with great personalities. True to their name, these freshwater shrimp come in the brightest shade of cherry and are a popular choice for small tanks.

Beyond its bright, colorful body, the cherry shrimp is also known for its active and playful nature. These small shrimp will dart around your tank and provide a lot of interest for you and your guests.

18. Clown Killifish

clown killi healthy adult female in bright coloration

The clown killifish’s distinctive body and fun personality make it a great addition to your 2-gallon tank. This colorful fish comes in shades of blue and yellow, with black stripes at the base of its tail.

They also have an active and playful nature, so they’re sure to provide lots for you and your guests to enjoy! Compared to other fish on this list, this one requires moderate care and maintenance.

19. Chili Rasbora

Mosquito Rasbora (Boraras brigittae) Beautiful Endemic Ornamental fish from Borneo

The chili rasbora is a small, shoaling fish that comes in a variety of colors, including red, yellow, and black. This hardy fish is tolerant of a wide range of water conditions and makes a great addition to any aquarium.

They grow to about 2 inches in length and are very active swimmers. If you take proper care of them, they can live up to 10 years in captivity.

20. Sparkling Gourami

Trichopsis pumila,
Image Source:

The sparkling gourami is a beautiful fish with a shiny silver body and bright red fins. This peaceful fish grows to about 3 inches in length and does well in a community tank.

They are schooling fish and should be kept in groups of at least six. The sparkling gourami is a hardy fish that can tolerate a wide range of water conditions.  

21. Honey Gourami

Honey gourami Trichogaster chuna tropical aquarium fish in fish tank. aquaria concept

Like the sparkling gourami, the honey gourami is a peaceful fish with brightly colored fins and an interesting patterned body. The honey gourami also grows to about 3 inches and does well in a community tank. 

22. Scarlet Badis

Scarlet Badis (Dario dario)
Image Source :

Scarlet Badis are known for their beautiful coloration and interesting behavior. These small fish come in shades of red, orange, and yellow and have a unique black stripe that runs the length of their body.

They are schooling fish and should be kept in groups of six or more. Scarlet badis are hardy and can tolerate a wide range of water conditions.

23. Dwarf Pea Puffer

Dwarf Puffer (Carinotetraodon travancoricus) swimming

The dwarf pea puffer is a small, but feisty fish that’s sure to add some excitement to your tank. Though small, the pea puffer is a territorial fish that should be kept alone or in small groups.

24. Harlequin Rasbora

Aqua Huna Red Slender/Espei Harlequin Rasbora

Harlequin rasboras require minimal care and are a hardy species. Its diet consists of mostly small invertebrates and it should be kept in a school of six or more.

These fish come in a variety of colors, including red, yellow, and black. They grow to about 2 inches in length and are active swimmers. 


The beauty of fish keeping is that there’s always something new to discover. If you’re looking for interesting and hardy fish for your 2-gallon or 2.5-gallon tank, the fish on this list is a great place to start. Thanks for reading, and please leave a comment below if you have any questions!

Wanda is a second-generation aquarist from the sunny tropics of Malaysia. She has been helping her father with his freshwater tanks since she was a toddler, and has fallen in love with the hobby ever since. A perpetual nomad, Wanda does her best to integrate fish-keeping with her lifestyle, and has taken care of fish in three different continents. She loves how it provides a nice break from the hustle and bustle of life.

1 thought on “Best Fish for 2 And 2.5 Gallon Tanks – Stocking Tips & More”

  1. I do have a question! the community dwelling fish, you said they should be kept in a group of 6 or more. is that too many fish to keep in the 2 gallon tank? also for the non aggressive, non community tank fish would it be a good idea to keep them in twos for a little company or just stick to one?


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