The 18 Best Fish for 2 and 2.5 Gallon Tanks in 2023

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A 2.5 fish gallon or commonly known as a Nano tank (any tank below 5 gallons is generally known as a Nano tank) can add an aesthetic touch in a small space or office in your home. This small 2.5 gallon tank can be placed in any area without much thinking. This tank requires less exertion into cleaning, comes at a low price and is simple to keep up, along with that, it can house a decent number of fish. A small tank is always easy to manage and can be the best option for a beginner. However, it can regularly be trying to choose what sort of fish to pick. However, with such a small size tank of 2.5 gallons, it can always be a confusing decision to find the best fish for the tank. So, down below, I will be discussing the best fish for a 2.5 gallon tank. But before that, let’s have a look at the best 2 to 3-gallon tanks out there!


Best Fish for 2 and 2.5 Gallon or Nano tanks!

1. Bloodfin Tetras

General Features:

Care Easy

Tank Temperature 70-80 Fahrenheit

Ph Level 6-8

Size 2-2.5 inches


Bloodfin tetras
Bloodfin Tetra


Bloodfin tetras are small yet elegant-looking peaceful fishes. You can keep at least 3 in a 2.5 gallon tank; they don’t like to stay alone, so make sure to buy at least 2-3 for your tank. You can keep a maximum of 5 bloodfin tetras in a 2.5 gallon tank. They are very active and can easily live up to 10 years, but for that, you need to take care of them properly and provide them with proper treatments. Bloodfin tetras can be easily recognized due to their unique feature of the silver body.

The bloodfin tetras are related to ember and neon tetras, and they can easily survive even in cold waters. Water temperature from 68º to 78º Fahrenheit is sufficient, however the fish show better shading at the higher finish of the range. They are not fastidious about water science, doing admirably with a pH of 6.0 to 8.0 in delicate to moderately hard water. Their primary food includes freeze-dried foods and flakes.


2. Cory Catfish

General Features:

Care Easy

Tank Temperature 60-70 Fahrenheit

Ph Level 5.5-7

Size 1-2.5 inches


Cory Catfish
Cory Catfish


Another absolutely beautiful small fish, they are a suitable match for a small tank since they dont grow that big even in their adulthood. It is mandatory that you should keep them in a group of three instead if alone; they often cannot survive alone and will die very soon. The fish is an imperative decision for a little aquarium as a result of the blend of character and utility. That is the reason Cory Catfish can be a suitable option for a small tank.

Corys are tough fish for their size and are staples in freshwater network tanks. Cory Catfish are frequently portrayed as defensively covered catfish, because of their plates of bonelike material running the length of their bodies. There are various Cory Catfish types, all differing in size and shading.


3. Betta Fish

 General Features:

Care  Very Easy

Tank Temperature 78-80 Fahrenheit

Ph Level 7.0

Size 2.25 inches


Betta Fish
Betta Fish


One of my most favorite fish for a small tank, and there are many reasons for that. Unlike other fishes, it is advisable that you should keep a betta alone in a tank, and you can keep them in 2.5-gallon tanks. But, we recommend keeping them in at least a 5-gallon tank. The bigger the tank, the happier your betta will be.

It is mandatory not to keep two males together because they are also known as fighter fish, and they will fight with full aggression causing injuries to the other. Most importantly, they don’t make your tank dirty; they are very clean; hence you don’t need to change your aquarium water frequently if you have a large tank. But if you are keeping your betta in a 2.5-gallon tank, we recommend changing the aquarium water twice a week.

There cannot be a better fish than a Betta for a beginner aquarist.


4. Small Barbs

General Features:

Care  Easy

Tank Temperature 75-80 Fahrenheit

Ph Level 6.8-7.8

Size 2 inches


Small Barb
Small Barb


Small Barbs fish can be of different categories; there are many varieties of barbs. But, the checkerboard barbs and the cherry barbs are the most suitable for a 2.5 gallon tank. Since these fishes are very small and keeping them in small numbers often causes aggression between them, so you should at least keep five barbs in your 2.5-gallon tank.

These Small barbs are shoaling fish and should be kept in bunches in the aquarium. In the same way as other little shoaling fish, these small barbs also have a hierarchy where each fish has a degree of strength. So as to consistently strengthen the group structure, hence quarrels and pursuing is a customary event for them.


5. Small Tetras

General Features:

Care Easy

Tank Temperature 77-82 Fahrenheit

Ph Level 5-7

Size 2 inches


Neon Tetras
Neon Tetras


Tetras can be of different types also, but all of these tetras look great in a small 2.5 gallon tank. Neon and black tetras stand out from the rest of the tetras.

You might need to place some additional plants inside since these fish love to hide and stay in peace.

They are different, so they are the right decisions for a little aquarium. All things considered, these fish are serene. In the event that you need peaceful however vivid fish, there are some Tetras fish you can keep in a 2.5 gallon tank, for example, Neon tetra, Cardinal tetra, Lemon tetra, and Black tetra. Ruby tetra, so you can choose the one that you like the most. You can add 23 tetras at maximum in a small tank.


6. White Cloud Mountain Minnow

General Features:

Care Easy

Tank Temperature 60-72 Fahrenheit

Ph Level 6.0-8.0

Size 1-1.5 inches


White Cloud Mountain Minnow
White Cloud Mountain Minnow


These fishes are kind of the same as tetras and can adapt well to small tanks in both freshwater and cold water; hence you do not need to worry about buying expensive heaters for them.

The White Cloud Mountain Minnow is a gorgeous little fish from the waterways of China. The scales look absolutely gorgeous and reflect a shocking exhibit of colors. They are not very chaotic, and it is effortless to keep. More importantly, they can be taken care of quickly in community tanks.

These fishes match quite a bit in nature and look with neon tetras and hence can be kept with small tetras also. These fishes can leave for up to 5 years under proper care and treatment. But, they like to stay in a group, and if kept alone, they often lose color. So, always try to place a few of them together.


7. Danios 

General Features:

Care Moderate

Tank Temperature 70-78 Fahrenheit

Ph Level 7.0-7.8

Size 2-2.5 inches




Danios are very to keep and are an ideal fish for a beginner. Even though, I have stated an ideal temperature and condition for them; they can adjust easily to any type of temperature and condition. Danios are very active and have a versatile diet; you will be able to feed them any fish food you want.

They can easily be recognized among the rest of the fishes due to their unique and bright horizontal stripes. Another good-looking danio species is zebra danio; you can also look after them while selecting the best fish for 2.5 gallon tank.

Danios like to stay in small groups and can even stay with other fish. However, don’t keep them fishes that have long fins like betta; they will bite and tear the fins.


8. Kuhli Loach

General Features:

Care Bit hard

Tank Temperature 75-86 Fahrenheit

Ph Level 5.5-7.0

Size 2-4 inches


Kuhli loach
Kuhli loach


For those of you who are looking for something unique for your 2.5 gallon tank, you can definitely buy Kuhli Loach. They will hide most of the daytime and is active at night; they stay at the bottom of the tank. They will, in general, be strong and seemingly perpetual in the aquarium and coexist well with their own sort just as others.

They have a strict diet, so it is not recommended for beginners. You need to select their food carefully if you wish to keep them for them to survive for many years.

Kuhli Loach often likes to stay hidden, so if you fish to keep them, it is mandatory that you make some type of hidden spots like tunnels of the cave and they often like to sink at the very bottom of the tank.


9. Small Livebearers

General Features:

Care Bit hard

Tank Temperature 74-78 Fahrenheit

Ph Level 7.0-8.4

Size ½ – ¾ inches.


These fishes are tiny and look kind of cute in small tanks and are available in a variety of colors, but they make an awful amount of waste in aquariums. Hence, if you really get them, you have to clean your eater more often than regular, which can be quite painful.
A pro tip from expert aquarists is that if you wish to keep small livebearers in your 2.5 gallon tank, you should decrease the number of fishes so that they cannot make a huge mess.

These fishes also breed very fast compared to other fishes in this category, so your tank will soon be filled with tiny fishes.


10. Black Molly 

General Features:

Care moderate

Tank Temperature 68-82 Fahrenheit

Ph Level 7.0-7.8

Size 2-3 inches


black molly
black molly


The Black Molly has short fins with all-black color. They may have patches of a slight gold or silver tinge as a baby, yet will grow out of this with age. This kind of fish is known for its high adaptability and versatility. They can have the option to live in freshwater, saltwater, just as saline water

This fish is ideal for your little tank. They permit you to get a community of fish with a wide range of types. On the off chance that you keep both male and female fish in a tank, it can breed and give birth to molly babies. But, black molly has a weird habit of eating their own babies.

So, in case you have a very small tank, dont put male and female together. And for babies, you will need to provide proper hiding spots. You need to have an appropriate filtration system for them since they dirty the tank more often.


11. Platies

General Features:

Care easy

Tank Temperature 70-80Fahrenheit

Ph Level 6.0-8.0

Size 2.5-3 inches




Platies have a sharp nose, huge eyes, and a fairly thick body from their noses to their dorsal blades. Their bodies tighten towards their tails, making them unmistakable from their midsections. They have little dorsal, buttcentric, and caudal blades and a fan-molded tail. They look very cute and are often liked by kids.

Platies are perfect for beginners and for 2.5 gallon tanks since they are very to keep and take care of. They come in a variety of color options: blue, red, white, yellow, and orange with different shades also.

They can be kept with other fishes; they can stay well in a community fish. However, it is important that you keep platies babies away from other fishes.


12. Swordtails

General Features:

Care moderate

Tank Temperature 65-82Fahrenheit

Ph Level 7.0-8.4

Size up to 6.3 inches




These fishes are sure to add more colors and versatility to your fish tank. Swordtails are very beautiful fishes, their extraordinary fins with a different range of colors make them unique, making them ordinarily alluded to as Red swordtails or Green swordtails.

They are not schooling fishes. However, they can live easily in groups. Something that makes them so wellknown is their toughness, as they easily survive in different conditions. They can easily fit and comfortably stay in a small area, which makes them an ideal choice for a 2.5 gallon tank

Swordtail can be fed both algae and proteins which includes worms, shrimps, etc.


13. Black Skirt Tetra

General Features:

Care moderate

Tank Temperature 70-85 Fahrenheit

Ph Level 6.8-7.0

Size 2 inches


It is not very hard to perceive a black skirt tetra due to its unique color and outlook. At first glance, you will see two vertical dark stripes on the front portion of the body with anal fins and dark dorsal. However, their color changes when they reach maturity which is usually after a year, the dark color starts to become a blur, and by the age of their color will be pale.

They like to live in softer and clean water, so you have to make sure to keep your water clean by providing a proper filter.

They do not like to live alone, so you must consider buying at least two of them, and they are very easy to keep among other tetras for beginners. Under proper care, Black Skirt Tetras will live between 3-5 years.


14. Blind Cave Tetras 

General Features:

Care moderate

Tank Temperature 68-77 Fahrenheit

Ph Level 6.5-8.0

Size 4.7 inches


Another breed of tetras is Blind Cave Tetras which is suitable for a small 2.5 gallon tank. Well, you might be wondering why am I discussing so many different breeds of tetras; tetras are one of the best fishes to place in your 2.5 gallon tank and hence it is worth mentioning all the different suitable breeds of them.

They Can live happily in cold water, so you do not need an additional heater or lighting. They are called blind caves for a reason, they do not have any sight and like to hide in caves; so, make sure to add a cave inside your tank.

Blind Cave tetras like different tetras are best kept in schools with their very own few species. However, It is important to place a screen on top of your tank because these tetras tend to jump when they are stressed out.


15. Wild-type Guppies

 General Features:

Care Bit Hard

Tank Temperature 78-82 Fahrenheit

Ph Level 6.8-7.6

Size 1-1.5 inches




Guppies should not be a new name for you if you are an enthusiast in the field of aquarium. These are some of the most commonly kept fishes in tanks. However, Wild Type Guppies are a bit exotic than regular guppies and can live well inside 2.5 gallon tank.

Wild Guppies are small and look good, more importantly, they only require a couple of quarts of water to live. Typically, these fish are kept in squeezed conditions. It’s critical to isolate just as eliminate any debilitated ones from the gathering. However, they become easily sick, and hence you may require assistance from an antibacterial medication for the treatment.

The entirety of the wild-type guppies are deft feeders that will touch on aufwuchs and algae the entire day yet are not above eating a little bug, a scavenger, or even a little fish on the off chance that they get an opportunity.


16. Salt And Pepper Pygmy Cory catfish

 General Features:

Care Hard

Tank Temperature 72-79 Fahrenheit

Ph Level 6.2-7.2

Size 0.75 inches


These fishes are very time, even smaller than guppies and that makes them even more suitable for a 2.5 gallon tank, and thus it was mandatory to include them in the list of the best fish for 2.5 gallon tank.

It is a vivified, particularly schooling fish that is ideal for the community and planted aquarium. As its name proposes, it has a light tan body secured with dark and glossy silver spotting and broken striping.

The Salt and Pepper Pygmy Cory catfish is an extremely quiet schooling fish that is viable with most Nano aquarium creatures. It is an exemplary scrounger and will possess and take care of at the aquarium floor, which ought to be included sand or smooth rock.

Read more: Best Fish for 5 Gallon Tanks


Other Aquatic creatures that can be included in a 2.5 Gallon tank

 It isn’t always necessary to include only fishes in your 2.5 gallon tank if you want something more exclusive you can certainly look into these amazing aquatic creatures which will make your 2.5 gallon tank look more beautiful and exquisite.


1. Cherry Shrimp

General Features:

Care Easy

Tank Temperature 57-86 Fahrenheit

Ph Level 6.5-8.0

Size 1.6 inches


cherry shrimp
cherry shrimp


Cherry Shrimps, in general, are very easy to keep: even beginners can keep them easily following a few general guidelines. A Red Cherry Shrimp can be an extraordinary little freshwater shrimp to add to an aquarium. Their brilliant red shading truly adds magnificence to a tank, particularly one stacked with live green aquarium plants and dark rock or substrate.

Cherry Shrimp are dynamic and fascinating to observe.

Red Cherry Shrimp appear to be agreeable in set up aquarium water that is on the hard side, with a fair streaming ebb and flow. The key is to keep water conditions stable. It is important that you keep enough plants in your tank because your shrimp likes to hide, and they exhibit the most colour when they feel unstressed.

Red Cherry Shrimp taking care of isn’t troublesome in any way. Their eating routine incorporates fish chips, pellets, green plants. In general, they have a pretty straightforward and simple diet. Moreover, you will be able to keep them with bettas also so you can have more versatility in your 2.5 gallon tank.


2. Zebra snails

General Features:

Care Easy

Tank Temperature 70-80 Fahrenheit

Ph Level 7.5-9

Size 0.5-1 inches


Zebra snails
Zebra snail by


Another easy to care good looking creature that you can consider keeping in your 2.5 gallon tank is a Zebra Snail. Zebra snails are commonly available freshwater snail right now, and they are very popular for their unique smooth looking golden-brown colour shell. Their shell has dark black stripes running back from the gap to the summit, making a zebra-like look.

They have gained popularity for being remarkable tank cleaners and one of the most capable algae eating snails around. They keep your substrate clean and the right shading. Truth be told, Zebra snails are generally accepted to be the absolute best snail in the aquarium pastime for pulverizing algae off of glass, rocks, live plants, driftwood, and different kinds of enrichments that you use inside the tanks.

However, do keep in mind they can’t reproduce in fresh water; they require saltwater to reproduce. They are peaceful, and hence you can keep them with any other fishes and plants without any tension.


Things to consider while buying the best 2.5-gallon tank

 You cannot simply go and buy the best fish for 2.5 gallon tank without knowing how to choose the perfect 2.5 gallon fish tank. There are few things that you need to consider while buying a 2.5 gallon tank.



For any fish tank, regardless of the size, it is important that you choose a proper filter to ensure clean and safe water for your fishes and other aquatic creatures in your aquarium. Chemicals and harmful substances like ammonia often spread toxin it puts the strength of fish in danger. For the most part, the ammonia is radiated from their bodies in the type of waste.

But, while choosing the filter, it is mandatory that you do not choose a filter which is too strong or else your fish will get sucked in. This factor is most commonly observed with fishes like betta and other baby fishes.

Notwithstanding, it is consistently a conventional plan to think about the tank with filter. And it is always seen that when the water is cleaner, the fishes will remain more joyful inside and will live more.



This factor is additionally significant when you utilize a fish tank because inappropriate lighting can prompt high water temperatures.

The 2.5 gallon fish tank isn’t so little in size, and they need proper lighting conditions, and it is said that appropriate lighting will ensure that the fishes and aquatic animals that you had kept inside your 2.5 gallon tank can openly swim inside. It will likewise assist you with performing simple cleaning and taking care of during the night.

You can either buy additional lights or buy a tank with built-in lighting. It is better that you buy a tank that comes with lighting already because it will save you from the hassle of getting separate lighting as well as it will encourage the development of plants because this imitates the actual underwater conditions.

However, do not use radiant bulbs since they can keep you from controlling the water temperature.


The Fish size

Since you are working with a small tank of 2.5 gallons, it is important that you choose the size of the fish carefully. In the event that you are unconscious of the size of the fish, it gets hard to pick the best 2.5 gallon fish tank because the key animals inside our tank will be fish and we have to know how much space they will involve.

If you want your fishes to stay healthy and live happily inside your tank, you should give your fish sufficient space to live in. So, it is important for you to consider the ratio of the fish you are going to keep along with the size of the tank. If you are still unsure on which fishes to pick for your 2.5 gallon tank, you can scroll up and read my list of the best fish for 2.5 gallon tank which will make your choice much easier.

But, do keep in mind since 2.5 gallon is not a very large fish tank so do not keep very large size fishes in them. Try considering small sizes fishes which will make your tank look more beautiful and stand out in your homes and offices.



Every fish requires a different temperature to stay healthy, so it is very important that you should control the temperature of your water in the proper range. There are few fishes which do not require any heaters. But most fishes do require a heater.

Do consider buying a good heater with your tank and control the temperature according to your requirement, but keep track because sudden and increase and decrease in temperature will make your fishes more vulnerable to infections and diseases.

However, if you do not wish to buy additional heaters you can always buy 2.5 gallon fish tanks which already comes with prebuilt heaters and these heaters are more easy t0o setup than the aftermarket ones.


Proper Cleaning

It is commonly seen that aquarists often make the mistake of feeding them too much, but it is not wise to do that since this will create lots of mess in the tank.

To ensure the successful working of our 2.5 gallon fish tank, the proper cleaning should be taken into consideration. For the most part, such tanks should be cleaned at least once every week. By cycling your tank appropriately, you can keep your fish from passing away at an early age.

We have to remember that little fish tanks ought to be cleaned significantly more regularly than more huge tanks. The fish waste, garbage, and different contaminations develop rapidly in the 2.5 gallon tanks. In this manner, they should be cleaned routinely. We have to plan to clean them once every week and ensure we perform standard water changes.


how to set up a 2.5 gallon tank


How To Setup a 2.5 Gallon Tanks:

This is an additional setup guide for all my readers out there; you can follow this step-by-step guide.


1. Placement

Placing your 2.5 gallon fish tank is very important, not just for the looks but also for the proper health of your aquatic animals inside the tank. All things considered, get it far from direct daylight, out of the range of kids, and also away from where there is a lot of people moving.


2. Addition of Substrate and other decorations

After placing your tank, you need to add substrate which can either be sand or gravel and make sure to slop them towards the back. But, it is necessary that you should observe for the first few weeks before releasing your fish inside the tank. You can also add wood or other decorations according to your choice, but make sure that you don’t put something that your fishes won’t like


3. Addition of Water and plants

Now start adding water slowly in your tank in such a way that is doesn’t cause clouding (you can use an airline). Fill the water to the substrate level and plant your plants using tweezers.

Now you need to half fill the tank with water using the airline, and you need to fill the rest half with a bucket using the real filter chamber, but make sure not to dismantle your plants.


4. Installation

It is now time for you to set up all your equipment in your aquarium. This includes filter, heater, light. Etc. after you are done installing everything, turn on your filter and wait.


5. Waiting

If you have followed the upper steps properly, you are already done with setting up your 2.5 gallon tank. Now you need to wait for your tank to mature. You are not yet ready to release your fish inside the tank. After waiting for around 24-48 hours, you can start to add fish slowly.


Frequently asked questions


1. How Many fish I can add to a 2.5-gallon tank

 Since 2.5 gallons is a small fish tank, you should not overcrowd your fish, and you must provide them with sufficient spaces. Properly study the fishes you want to keep and the area they need to survive happily, and you can always read our list of the best fish for 2.5 gallon tank.

In general, you can add around 23 moderately sized fishes, and you can also consider adding other aquatic animals like shrimp and snails along with some plants.


2. How to Properly do maintenance?

Even though a 2.5 gallon tank is small than traditional tanks, but they do require proper maintenance.  To guarantee solidness in your tank, try to change 50 per cent water week by week with dechlorinated and temperature-balanced water.

Also, Tap water can change the ph. Level of the water, so to avoid this problem, try to use re-mineralized water.


3. Can I keep two male bettas together?

As I discussed earlier in my list of the best fish for 2.5 gallon tank, you should never keep two male bettas together. They are aggressive in nature, so they will fight with each other, eventually killing one. However, in a 2.5 gallon tank, you can keep two females and one male easily.



A 2.5 gallon tank can be a perfect choice for a beginner aquarist or for someone who doesn’t have much space in-home or office, but still wants to keep a fish tank. A 2.5 gallon tank is easy to maintain compared to other bigger tanks.

With such a small tank, it can always be confusing on what fishes or aquatic animals that can be kept. Hence this list was created so that you select the best fish for 2.5 gallon tank. I didn’t just give you a list of the best fish but also included everything else that you need to know regarding 2.5 gallon tank including a very easy-to-follow setup guide.  There can be no best option than a 2.5-gallon fish tank to start your aquarist journey. So what are you waiting for? Just make up your mind a get a 2.5-gallon tank and get indulged in the beauty of the underwater world.

7 thoughts on “The 18 Best Fish for 2 and 2.5 Gallon Tanks in 2023”

  1. 2 gallon tanks should never be used for any fish. 5 gallons for a betta sized and under should be the bare minimum size. Anything under that is just a tiny torture chamber for the fish. Please don’t promote this. Too many people think it’s okay to have a fish as a decoration you put on a shelf. Fish are NOT shelf decorations! If you’re going to have a fish in captivity, the least you can do is give it enough room to swim. Tiny tanks mean you’d have to change the water more frequently which can cause more stress to the fish. If you don’t change the water frequently enough, you run the risk of creating illness. Fish are delicate and need to be cared for appropriately. A tiny tank is NOT appropriate.

    • ok, chillax. we don’t all have space for a large aquarium. 2.5 gallons is more than sufficient for smaller fish. The article isn’t “promoting” anything- it’s simply listing info. If you feel so strongly about nano tanks, I suggest writing to your congressman, or picketing in front of Petco. This article was helpful for the info I needed. Move on with your negativity.

  2. Unfortunately this article’s statement that betta fish can survive in a tiny fishbowl leads me to not be able to trust any of the other information in it. While bettas CAN survive in 2.5 gallon tanks, “survive” is the operative word. The actual recommended size is 5 gallons and anything less than that can lead to health problems. Keeping a betta in a tiny fishbowl WILL lead to them dying early.

    • When I was a kid I had a betta in a gallon tank. he lived for 6+ years and was a very happy fish (spunky as far as fish go lol) i would never get a tank that small again, but it is possible they can thrive lol

  3. I have bettas – All in 3 – 5 gallons in different rooms of my house and all blow bubbles. I would say happy fish. Only one is in a 5 gallon and she won’t blow bubs and is housed with a manage a trois of danios. I know that it is ideal to have larger space for your fish, but HEY! I swear mine are happier than they were in those dirty petco cups.

  4. Helpful article, thank you. A tiny suggestion: add photos of the fish to your article. It will add color to the page and will also help readers. (from one blogger to another.) 🙂


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