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Smallest Freshwater Aquarium Fish

So you don’t have a lot of space for your new freshwater aquarium. So what? Just because you are restricted on size doesn’t mean you have to be restricted on the quality of your homemade underwater ecosystem.

There are plenty of small freshwater fish that will not only survive but thrive in a tiny tank. If you’re looking for the smallest freshwater aquarium fish, we’ve created a massive collection for you here. Continue reading to learn more about the best options for fish to keep in your small home aquarium.

Smallest Freshwater Aquarium Fish

22 Smallest Freshwater Aquarium Fish

1 Ember Tetra

Ember Tetras
Photo by Peter Maguire

Ember Tetras are native to Brazil, and they make a great choice for a small fish tank. They are absolutely lovely to look at, with striking orange and red translucent bodies. They love heavily planted tanks, as they prefer to spend most of their time swimming among the vegetation. They prefer somewhat acidic tanks and are very easy to maintain, eating a mixture of dried and flake foods. They will even gobble up live foods like brine shrimp!

2 Green Neon Tetra

Green Neon Tetra
Photo by S.R.G – msucoo93

Green Neon Tetras are freshwater fish that only grow to around an inch or so in size. They have defined blue-green patterns and are the perfect size for a small freshwater tank.

These fish are gorgeous to behold and also peaceful to other fish. They will eat a mixed diet comprised of a variety of pellets and live foods. You will want to keep an eye out for Neon Tetra Disease, which is a very common illness to which these fish are exceptionally prone. Otherwise, there’s not much you need to do to help these lovely fish thrive!

3 Pygmy Corydoras

Pygmy Corydoras
Photo by Antje

The Pygmy Corydoras is a great species to raise if you decide to keep some Ember Tetras. This fish species is very active, preferring to be housed with other species of fish, as it is quite social. They also thrive among water snails and shrimp.

These fish prefer to inhabit the middle levels of the tank, moving about the aquarium in shoaling groups. Pygmy Corydoras are silver with black streaks that extend from their caudal fins to their mouths. They are easy to care for and easy to breed, with females producing around 100 eggs at a time. They will eat a variety of foods, including flakes and sinking wafers.

4 Fancy Guppy

Fancy Guppy

Fancy guppies are tiny, curious fish that do well in small tanks – even those that are smaller than five gallons! Just make sure the water is warm and the tank is clean, and it will be smooth sailing. These schooling fish like to be kept in groups – to avoid overcrowding, keep them in groups of five.

5 Neon Tetra

Neon Tetra

Neon Tetras, growing to around 1.3 inches in size, are some of the most beautiful and most popular freshwater fish species. They love to live in tropical aquarium environments with warm waters. They like to hang out in the middle levels of the water column and get along well with almost every other kind of community fish – as long as they are around the same size.

These fish will eat just about anything, preferring a wide variety of flake foods. You don’t need to watch out for with these fish, except for fading colors. A loss of color often indicates that these fish are experiencing some form of stress.

6 Sixray Corydoras

Sixray Corydoras

The Sixray Corydoras is one of hundreds of different Corydoras species. These bottom feeders love both plant and meat-based foods, and like to live in tropical settings. They prefer tanks with plenty of vegetation, in which they will hide their fry.

These fish are native to South America, primarily to the lakes and rivers of brazil. They rarely grow over an inch in size and can tolerate temperatures ranging from 72 to 77 degrees Fahrenheit and pH between 6 and 7.2

7 Pea Pufferfish


These fish do best in temperatures of around 7 7 to 79degres Fahrenheit. Only growing to about an inch and a half in length, the Pea Pufferfish is also known as the Pygmy Puffer Fish. These fish have only come into the aquarium hobby within the last few years. However, they’re a great choice – because they are so small, they fit well in tiny tanks. These fish are native to Southwest India and differ from marine pufferfish in that they prefer freshwaters.

These fish can be somewhat aggressive at times, so you will want to keep an eye on them if you are keeping them in a crowded tank. They are carnivores so they might eat on smaller species like live snails. They will eat some plant flakes, too, but they prefer meaty diets with lots of worms and insects.

8 Salt And Pepper Catfish

Salt And Pepper Catfish
Photo by Andrew


Salt and pepper catfish only grow to about 1.3 inch in length. Preferring temperatures between 75 and 78 degrees Fahrenheit, these fish are native to South America and are frequently found in wetlands. They prefer shallow water and often rise to the surface of the tank to gulp in oxygen. This is normal behavior, but if you notice other is doing it, it could be a sign that the oxygen in the tank’s water is too low.

These fish do well in groups, preferring to eat various types of pellets and flakes. They also like to munch on brine shrimp. You should house them in a densely planted tank that will be similar to their natural environment.

9 Betta Splendens

Betta Splendens
Photo by Antoniolpiras


If you have a small tank with few or no other inhabitants, a Betta fish might be a good choice for you. Also known as the Siamese Fighting Fish, this species can behave quite aggressively towards males of its own species – fighting to the death in most cases. Sometimes, male bettas will even exhibit this aggressive behavior towards females or other fish of different species.

However, you can keep a single Betta on his own in a small tank and he will be perfectly content. Just make sure the current isn’t too strong and provide plenty of decorations and hiding spots.

10 Scarlet Badis

Scarlet Badis
Photo by Aquarist Magazine

This small fish prefers to live in warm tanks of around 75 to 79 degrees Fahrenheit. It can, however, tolerate a wide range of pH values, with the ideal being between 6.5 and 7.6 Growing to only a couple centimeters in size, there is a great deal of sexual dimorphism in this species – the females will be almost a full centimeter smaller than the males. Males also have prominent ventral fins.

These fish like tanks with plenty of live plants and other decorations, which helps reduce the Scarlet Badis’ natural predatory behavior. Plants will help restrict the fish’s line of sight, making it less likely that it will act out with aggressive actions.

11 Sparkling Gourami

Sparkling Gourami
Photo by Mike MacLeod

Sparkling Gouramis are absolutely beautiful, available in shades of blue, red, and green. They stand out quite well in most fish tanks and are shaped like arrowheads. They aren’t terribly friendly, meaning you might not want to house them with fish like bettas, particularly males.

However, they are not too difficult to care for. They have unique labyrinth organs that make it possible for the fish to engage in alternative breathing techniques. They will eat a variety of foods, including bloodworms, brine shrimp, and more.

12 Hara Jerdoni

Hara Jerdoni

The Hara Jerdoni fish was first discovered in India, and it is one of the tiniest species of catfish. As bottom-dwelling, heavily whiskered fish, these adorable fish spend most of their days lying sedentary on the bottom of the tank. They like to live in small tanks, preferring to not have to move a lot.

Because these fish tend to stay in one place, they are good companions for other more active fish. They need tanks with above-average levels of oxygen and they also need some sort of cover. This cover, which can be provided with various hiding places like rocks, plants, or caves, gives the fish a place to lounge and hide. They will eat just about any type of food, including frozen, live, and dried options.

13 Endlers Guppies

Endlers Guppies
Photo by Peter Maguire

These fish are some of the most popular choice for small freshwater tanks. They are gorgeously colored and while similar to regular guppies, growing to less than two inches in size, they are also distinct.

These fearless fish are very active, spending most of their days exploring the tank as they eat up any available algae. They do best in warm water, with ideal temperatures between 75 and 81 degrees Fahrenheit. You will want to invest in a tight-fitting lid cover, as jumping is a favorite pastime of this fish. They get along well with other species and love to play.

14 Licorice Gouramis

Licorice Gouramis
Photo by Oceancedar

The name sounds tasty, right? Well, these fish are too cute to eat! They are some of the smallest freshwater gouramis you will find, growing only to 1.3 inches in length at most. They are gorgeous to look at with silver and black patterns.

These fish should be housed in shady tanks, particularly those that have lots of live plants and driftwood. They are peaceful and will eat a variety of meat and plant-based foods. Licorice gouramis are excellent community fish, getting along well with other amicable fish. They like acidic water that is well-filtered.

15 Least Killifish

There are several types of killifish, but this one in particular is native to the southeastern United States. Related to both guppies and mollies, this fish species is a livebearer. This means that it gives birth to live young instead of laying eggs.

Least Killifish only grow to about an inch and a half in size and can thrive in aquariums as tiny as three gallons. You don’t need to be too attentive when it comes to the water quality in the tank – they can thrive even in unstable conditions. They aren’t terribly colorful, but they are peaceful and easygoing and will get along well with your other fish.

16 Norman’s Lampeye Killifish

Norman’s Lampeye Killifish is another species of killifish that can thrive in a small freshwater tank. These fish are a great choice for invoice aquarium hobbyists. They only grow to about an inch and a half in length and so you can easily keep a group of three to five in a tank as small as five gallons. They do, however, prefer plenty of live plants in which they can hide.

17 African Dwarf Frog

African Dwarf Frogs
Photo by Peter Maguire

You don’t have to stick to fish for your small aquarium! African Dwarf Frogs are commonly kept in paludariums but you can also keep them in small aquariums. As long as you have a secure lid, you should be fine. They don’t need overly warm water and provided that you give your frog some surface space between the water and the top of the tank so that he can breathe air from time to time, you will be good to go.

18 Dwarf Gourami

Dwarf Gourami
Photo by Bosscock_uk

Dwarf gouramis can be kept in tanks of around five gallons. They can breathe air above the water and do well in tanks with minimal levels of oxygen. As long as you keep your tank clean and provide your dwarf gourami with a healthy diet, he will do great in a smaller tank.

19 Ghost Shrimp

Ghost Shrimp
Photo by Matthew Singleton

Ghost shrimp, like African Dwarf Frogs, aren’t technically fish. You can keep these creatures in your small aquarium, too! Although they are often kept as food for other fish, they are unique species that are fun to raise in their own right. You can keep a group of six shrimp in a tank that is less than five gallons, giving you plenty to look at even if you don’t add any fish! Feed your ghost shrimp sinking pellets and algae wafers – otherwise, they’re easy to care for.

Remember, you’re not restricted to ghost shrimp if you want to add invertebrates, either! You could also add red Cherry Shrimp or Crystal Red Shrimp, both of which make excellent additions to freshwater tanks. You could even start a shrimp-only aquarium!

20 Dwarf Puffer

Dwarf Puffer Fish
Photo by anna pang

Did you know that not all puffer fish are designed for saltwater? In fact, the Dwarf Puffer is a great species for a freshwater tank, as it’s native to a freshwater environment. This fish thrives in small aquariums and only grows to about an inch in length. It can thrive in five-gallon aquarium. However, if you plan to add multiple fish, you might want to invest in a larger tank.

These carnivorous species will require lots of meaty foods. You should also feed live snails, which will help provide valuable nutrients and will help to grind down the razor-sharp teeth of these predatory fish. You should also provide plenty of live plants, vegetation, and driftwood to help make the dwarf puffer feel at home in your small aquarium.

21 Celestial Pearl Danios

Photo by Matthew Willis

These colorful fish are fun to watch, making them a popular choice for freshwater aquarium owners. These schooling fish should be kept in groups of four to six. Groups can be kept in tanks as small as five gallons, but larger is recommended if you have trouble keeping up with consistent water changes!

These omnivorous fish should be fed a combination of meat- and plant-based foods. They will eat anything from freeze dried bloodworms to algae wafers and only grow to about an inch in size.

22 Bumblebee Goby

Bumblebee Goby
Photo by Hristo Hristov

These unique fish may be last on our list, but they certainly are not least! Growing to only an inch and a half in length on average, these fish have bold personalities and can be somewhat territorial. You might want to be careful housing more than one Bumblebee Goby in the same tank.

These fish are easily outcompeted for food, so you will need to watch them carefully during feedings to make sure they’re eating enough. Besides that, they aren’t too difficult to care for, only growing to about an inch in size.

Finding the perfect fish for your freshwater tank can be a challenge. Selecting the wrong fish species can throw off the entire ecosystem.

Why jeopardize it? Instead, choose a fish that will get along well with your other small tank inhabitants and you’ll be getting along swimmingly!

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