16 Best Fish for 2.5 Gallon Tank – Tips and More

In this article, we discuss the best fish species for a 2.5-gallon fish tank, including betta fish, dwarf pufferfish, guppies, and endlers. We also provided some tips on maintaining a healthy environment for these fish.

You can keep many different kinds of fish in a 2.5-gallon tank, but it is essential to think about the type of environment you want to give your fish. Choosing the best fish for a 2.5-gallon tank is simpler than maintaining the tank. There are many fishes you can keep in a 2.5-gallon tank. All you need to do is choose them wisely.

Choosing The Best Fish For 2.5 Gallon Tank

Even though a small tank has less surface area to clean, maintaining the proper chemical balance is a more complex task. 

It is easier to maintain a smaller tank than cleaning a 10-gallon tank. If simple rules are followed, a 2.5-gallon tank needs to be cleaned less often with difficulty to clean.

When you choose a fish for your aquarium, consider things like the size and friendliness. 

People who have a lot of experience taking care of fish usually suggest that new fish keepers start with bigger aquariums.

On the other hand, having a smaller tank can still be just as fun and rewarding if you know how to care for it.

16 Best Fish For 2.5 Gallon Tanks: Our Picks

#1 Bloodfin Tetras

Bloodfin Tetras

The bloodfin tetra is a tropical fish that lives in freshwater and comes from South America. They are very active and calm simultaneously, but they do not move a lot. The Bloodfins should be added to your tank with other fast-moving fish like themselves.

#2 White Cloud Mountain Minnow

White Cloud Mountain Minnow

The White Cloud Mountain Minnow is a small, peaceful fish good for a beginner’s fish tank because it is easy to maintain. They are only 2 inches long, but they can live in different water conditions and thrive in a wide range of places.

The fact that they can handle changes in pH and temperature makes them a good choice for a tank that is still in the early stages of setting up.

#3 Cory Catfish

Cory Catfish

Cory Catfish are great for a small tank because they don’t grow too big even as adults. Keep them in a group of three instead of leaving them alone because they can’t live independently and would die quickly if left alone. 

These fishes are a must-have for any small aquarium because they are fun and valuable. Cory Catfish can be a good choice for aquariums that don’t have a lot of space.

#4 Betta Fish

Betta Fish

Betta fish, also known as Siamese fighting fish, is one of the most popular tropical freshwater fish on the market today, and they make up more than a quarter of all fish sales. One male Betta can live peacefully with other calm top-level surface dwellers like little tetras, rasboras, or gouramis. 

But when they live alone, they do better because there will be no injuries if two males fight over territory. The temperature should be 25 degrees Celsius or more for them to live. 

#5 Small Barbs Fish

Small Barbs Fish

They are called small barbs as they are a tiny, fast-moving fishes that are easy to find. In terms of color and design, there is something for every tank! These aquatic species are also often very easy to care for, which makes them a good choice for first time aquarium buyers.

#6 Kuhli Loach

Kuhli Loach

You can find them in many different shapes and colors, so it’s a good choice for small fish tanks. It’s also in this group because it is a small, bright fish that is easy to care for.

The Kuhli Loach has a long, slim shape that makes it easy to get into small places, so you’ll always be on your toes when you deal with them. They stand out due to the bright colors on their bodies. 

#7 Danios


Danios are a great first fish for someone who isn’t sure how to keep fish. They are easy to keep and maintain.They can adapt to any temperature or climate. If you keep them in an aquarium, you can feed them any fish food you want. They are the best aquarium fishes for a small tank.

#8  Clown Killifish

Clown Killifish

The stunning body pattern and fascinating behavior of the clown killifish make it a wonderful addition to any 2.5-gallon tank collection. This colorful fish comes in a range of blue and yellow colors, with black stripes running across the base of its tail.

They also have a vibrant and energetic personality, which means they’ll keep you entertained for hours. When compared to the other fishes, this one requires very little care and attention.

#9 Neon Tetra

Neon Tetra

It’s common for people to confuse the neon tetra with the cardinal tetra. People who want brightly colored fish in their aquariums often choose the neon tetra. It has a body that looks like a neon light, which allows them to put on a show of simply breathtaking colors.

#10 Black Molly

Black Molly

The Black Molly is unique because it has small fins and is all black. Younger fish may have spots on their skin that are a little gold or silver, but this will fade as time goes on. 

This type of fish is well-known for being able to adapt and be flexible in a wide range of situations. They can live in freshwater, saltwater, or even saline water, depending on where they are placed or born.

#11 Platy


Platy fishes are a great choice as first-time fish. It’s best to keep just one or two of these fish in your small 2.5 gallon tank, even though they like to be with each other . If you put too many fish in a small tank with a small filter, the filter won’t deal with all of the waste the fish make. To keep your 2.5-gallon tank clean, you should only have one or two platy.

#12 Wild–Type Guppies

Wild–Type Guppies

Wild-type guppies are the first strain of guppies that live in the wild. They are also called common guppies. They are easy going and can handle a wide range of water conditions, making them a good choice for aquariums. They also come in a wide range of colors, making them a good choice for aquariums. If you want to keep exotic guppies, they must be kept in freshwater to live and reproduce.

#13 Swordtails


These fish are likely to make your fish tank look better and have a more comprehensive range of colors. These fish are beautiful, and their fabulous fins, which come in various colors, help people tell them apart. 

#14 Black Skirt Tetra

Black Skirt Tetra

Fish with black skirts are another tropical fish that is becoming more popular in pet stores these days, but they aren’t the only ones. It should be easy to find a species that fits your needs because there are more than 20 to choose from. Some of them like their water to be colder, while others like their water to be hotter.

#15 Blind Cave Tetras

Blind Cave Tetras

This type of tetra comes from caves under the Mexican city of Monterrey. Because they can’t see, their other senses have become sharper. They use this to get around, and it helps them do that. Because of this, they can see movement and vibrations in the water, which allows them to find food when they are swimming.

#16 Peppered Pygmy Cory Catfish

Peppered Pygmy Cory Catfish

Pygmy Cory is another small fish that likes to swim in groups. You can find it in small bodies of water. It’s easy to grow them in a plant-filled aquarium because they don’t need a lot of attention and only grow to about an inch. They also have a lot of babies, so you can expect your tank to grow in size over time.

Because they are so small, even smaller than guppies, they are an excellent choice for a 2.5-gallon tank.

Suitable Non-Fish Species For 2.5 Gallon Tank

We recommend three non-fish species for a 2.5-gallon tank: Zebra Snails, Cherry Shrimp, and African Dwarf Frogs. Zebra Snails are great for cleaning tanks, while Cherry Shrimp are easy to maintain and visually appealing. African Dwarf Frogs, being small and easy to care for, are suitable for both beginner and intermediate aquarium enthusiasts.

Zebra Snails

Despite their small size, these microscopic snails are very strong and can handle a wide range of water conditions. They also eat algae and food that hasn’t been eaten, which makes them valuable to the fish in your tank.

They have gold stripes that make them look like zebras, making them a great addition to your tank. Even though they aren’t the most eye-catching, zebra snails may be helpful and easy to keep in your aquarium.

Cherry Shrimp

Cherry Shrimps, in general, are easy to keep, and even complete beginners can keep them if they follow a few simple steps. A Red Cherry Shrimp is a small, exciting shrimp that can be added to an aquarium as a decoration. 

With natural green plants and black rock or substrate, their bright red color adds a dash of elegance to any tank. You can also put cherry shrimp in your betta tank, but you should cut them back if you have a small tank.

African Dwarf Frog

A three-inch-long African Dwarf Frog is the smallest member of its family. They are much easier to take care of. They make a nice addition to your aquarium, even if it’s small in size. They are low-maintenance non-fish options for the beginner to intermediate level aquarium owner.

Things To Consider While Buying The Best 2.5 Gallon Tank

When choosing the best 2.5-gallon tank, consider its material, shape, and included accessories. Glass tanks offer clarity but are heavier, while acrylic is lighter but prone to scratching. Rectangular tanks provide more surface area for oxygen exchange. Additionally, look for tanks with quality filters and lights.

You can’t buy fish for a 2.5-gallon tank unless you know how to choose the best fish tank for your needs and wants. When you buy a 2.5-gallon tank, there are a few things you should think about. Here are a few things to keep in mind-

Water level

There must be the right amount of water in a tank before any fish can live there. You need to get your water parameters just right because there isn’t enough water to make up for any mistakes you make in a small tank.


Even if your fish tank is small, you need to choose the right filter for it to make sure your fish and other aquatic animals have clean and safe water. Poison is often spread with chemicals and toxic chemicals, like ammonia, which puts the fish’s health at risk. There is a lot of radiation coming from their bodies made up of waste.


Natural light is the best source of light, but if you want a brighter light source, you might want to buy an aquarium lamp with bulbs made for fish or some fluorescent tubes. In simple terms, don’t use regular light bulbs! Take no chances because they can start fires and even explode if they aren’t used correctly.

Fish’s Size

Because you will be working with a 2.5-gallon tank, you must choose the right fish for the space. A 2.5-gallon fish tank is hard to determine if you don’t know the size of the fish. The main animals in our tank are fish, and we need to know how much space they take up.


It would be best to give your fish the same conditions they would have in their natural water source to thrive in their home aquarium. Temperature-sensitive tropical fish from the northern hemisphere should not be kept with fish from the southern hemisphere or the other way around because this can cause stress, leading to sickness and death.

Cleaning In The Right Way

Aquarists often mistake overfeeding their fish, which leads to a lot of waste in the tank. The correct way to clean our 2.5-gallon fish tank is essential to ensure it works well. By making sure your tank is cleaned correctly, you may be able to keep your fish from dying at a young age.

How To Setup A 2.5 Gallon Tanks?

To set up a 2.5-gallon tank, start by choosing the right location, away from direct sunlight and drafts. Rinse the tank and accessories without soap. Add substrate, then fill the tank with dechlorinated water. Install the filter and heater, and let the system run for 24-48 hours. Add live plants, then slowly introduce fish. Monitor water parameters regularly.

The Location

The location of your 2.5-gallon fish tank is essential, not only for how it looks but also for the health of the aquatic species that will live there. Keep it out of the sun, out of reach of kids, and away from places where a lot of people move.

Addition Of Substrate And Other Things

There is a reason why this makes it more difficult for your tropical fish to swim against the current if they are trying to get away from something dangerous. To get the most out of this, put more enormous rocks in one part of your aquarium and smaller pebbles in the rest of the tank.

The Addition Of Water And Plants

It’s now time to add water to your tank in a way that won’t make it look cloudy. It would be best if you did this very slowly. Use tweezers to plant your plants in your container with water until the soil is reached. You should fill half of the tank with water with a hose then; you should fill the other half with a bucket of water using the natural filter chamber, making sure not to hurt your plants.

For your fish to stay healthy, you must keep the pH level in your aquarium the same. You can add aquarium salt at a rate of 0.1 percent. Make sure to wait at least 24 hours before making any more plans. 

The Installation

It’s time to install the tank. You must cycle your tank after it has been properly sealed and prepped. This is so that certain bacteria can break down dangerous chemicals into less hazardous molecules that tropical fish can eat.

Having To Wait

You have now installed your 2.5-gallon storage tank. A few more weeks and your tank will be ready. You aren’t prepared to let your fish out of the aquarium at this point in the game. After about 24 to 48 hours, you can slowly add fish to the tank.

How Many Fishes Are Suitable For 2.5 Gallon Tanks?

Ensure that you don’t overcrowd your fish and give them enough space to move around in your 2.5-gallon fish tank. Take a close look at the fish you want to keep, as well as the environment in which they will thrive. In general, a 2.5-gallon tank can hold up to 6 small tropical fish, and this is based on what kind and how big the fish you choose to add.

What All Fishes Are Enough For Your 2.5 Gallon Tank?

A 2.5-gallon tank may be smaller than a standard tank, but it still needs to be cleaned regularly to keep it in good shape. If you don’t have a lot of space for a big tank, a single male Betta with weekly water changes will be your only choice. 

Some Stocking Ideas That Can Come In Handy

In addition to several different ways of establishing appropriate stocking levels, there are other aspects to consider.

  • Before putting any fish in any tank, make sure the water is clean. The smaller the tank, the more critical it is to get the water parameters right.
  • Even though most fish don’t need a special diet, it’s important to remember that they need to be fed often. Overfeeding can hurt the water quality in a small tank, so feed your fish once a day.
  • One inch of fish for every one or two gallons of water. When you start with an approximation, this computation method can be beneficial. Whether or not you have live plants or the proper lighting and what kind of fish you want to keep are all things the rule doesn’t consider.
  • The surface area rule is used to consider the tanks’ different shapes. When the width and length are added together, the surface area of the tank is found. Water surface area rules say that for every twelve square inches of surface area.
  • Fish should be able to swim in water that’s close to what they’re used to. If you want to keep your aquarium at the right temperature, you’ll need an aquarium heater. Most freshwater and saltwater fish can handle a wide range of temperatures.


A 2.5-gallon tank is an excellent option for people who don’t have a lot of space at home or work but still want to have a fish tank.  Choose fish for your small tank based on factors like the size and shape of the tank, the temperature, how clean and clear your water is, and how often you want to clean it.

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