[Complete Guide] Best Fish for 5 Gallon Tank (With Pictures)

[Complete Guide] Best Fish for 5 Gallon Tank (With Pictures)

A five-gallon aquarium or cube is the smallest size that can acceptably keep fish. If smaller than that, then it translates into trouble in maintaining stable parameters. Even the littlest fish do require extra room to move and explore. This volume will limit your choices in fish but can still set up a vibrant and entertaining tank. Let’s go through Best Fish for 5 Gallon Tank.

Stocking a 5-gallon tank.

Any tank with a water capacity below 10 gallons is called a nano tank. The aquarist can use a 5-gallon storage tank to store small fish and invertebrate species. With its small size and capacity, it can be easy to overstock. This article enlightens you with the suitable fish species and inverts that can be kept in a 5- gallon tank and include the best stocking ratio and proper maintenance guidelines.

What freshwater fish should I put in a 5-gallon tank?

What freshwater fish should I put in a 5-gallon nano tank? With this limit on water’s volume, every centimeter counts. Most people have preferred to keep small creatures such as invertebrates and small fish with minimal food waste. Toxic waste builds up faster in smaller volumes of water, mainly if you are a new fish-keeper. I never assumed that five-gallon tanks would be as easy to keep.

Why have a 5-gallon tank

A 5-gallon tank nano tank is the better option for those who do not get much space. A smaller aquarium forces you to make more critical decisions and a righteous maintenance schedule. Most schooling fish are not ideal for a 5-gallon aquarium because they feel more anxious when alone. Small schools usually are what you can safely keep.

Overview of a 5-gallon tank

We could have 20, 55, or 100 gallons of water to fill, but the lack of bigger fish doesn’t mean we have a beautiful system. Nano tanks can equally look unique and full of life with the right fish and plants.

Why a 5-gallon tank?

5-gallon tanks should be the smallest you can get for success at fish keeping. The environment and water quality in highly unstable in those nanosystems. In this guide, we introduce the best fish for a 5-gallon tank. In a small place, an aquarium is a perfect decoration centerpiece.

Tropical freshwater 5-gallon tank basics

Keeping a nano 5-gallon tank is usually a challenge, but it will look like an underwater fairy tale land. Don’t be fooled by the fact that a smaller aquarium would require less work and maintenance than a large one. The numbers of the fish that can be kept in a 5-gallon container depend upon the species of fish you’re want to keep. We will be able to explain the proper design of a 5-gallon fish tank later on.

5 Gallon Nano Tank

There are a surprising amount of options available in regards to the best fish for a 5-gallon tank. While you can keep most of these fish in a 5-gallon tank, we usually recommend, if possible, a bigger tank. Fish like Guppies, Endler, and Killies can survive in little space thanks to their tiny size and habits. They are one of the easiest species for fishkeepers; they are not very demanding.

5 Gallon Tank Stocking Ideas And Combinations

We will show you several other species of fish for a 5 gallon. A bigger tank is easier to manage and allows you to keep a wider choice of fish. We decided to look at some of the best fish to help you get the best combo and the stocking ideas.

How do I stock a five-gallon fish tank?

If you are thinking about building a five-gallon aquarium, it’s simple to get confused by the overwhelming amount of information available on the internet. Keep reading to learn more about preserving one of these nano tanks!

What to consider when stocking a 5-gallon tank

A nano tank can reduce the number of your options of fish. Only some species are likely to prosper and do well in one of these small tanks. Certain varieties of reef fish can thrive in the small nano aquariums. Small tanks are attractively built, which can be kept at even a work table, and are often much cheaper to maintain than larger models.

How do you keep a fish in a 5-gallon tank?

Having and keeping your nano aquarium can be tricky. You should know how big your fish will get when fully grown. It would be best if you didn’t mix a peaceful fish with aggressive species. You can combine many species we list as above because their bioload is relatively tiny. You should find out which fish you want to keep. No overstock is advised.

How to stock a 5-gallon tank?

More life in your tank, more quickly it becomes dirty, needs more maintenance, and water changes. Slowly populate the tank, looking closely at your water parameters and your fish and system; small water tanks quickly become toxic. Live plants are welcome when they do not remove swimming space from fish.

How many fish can you fit in a 5-gallon tank?

How many fish you could keep in this size tank depends on the type of fish you intend to use. There are plenty of choices to choose from, but this article limits it to just some species that will prosper in the tank.

Set up of 5-gallon fish tanks

A 5-gallon tank is an ideal choice if you have limited space or want to start a small budget project. A giant aquarium is always recommended as even smaller critters need room for swimming and exploring. As counterintuitive as it sounds, nano tanks are cleaner and less dirty than bigger tanks. The waste your fish will inevitably create is a biological imbalance that becomes harmful and deteriorates the water quality within your nano tank. Design the tank with enough decorations to help fish hide and relax and leave enough room for free swimming requires a lot of creativity.

Planting and decorating

It is nice to cultivate some living plants in your nano aquarium for cycling nutrients, ornamental beauty, and providing a hiding place for the fauna. Decorations are exciting additions to aquariums because they contribute to replicating the native habitat of fish, shrimp, snails, etc. Add pieces of driftwood, rock, and caves in the tank, which inhabitants can hide in. Several of them should be acceptable for a five-gallon. Live plants not only improve the visual appearance of the tank they also promote water quality. The overall aim is to create a healthy and balanced environment for tank residents and ensure they thrive for a more extended period.


A well-planted tank will brighten every space and bring in a minor nature in your home. Some plants remain relatively small and do not require much maintenance. Even with a small amount of water, you can create your little forest.

Best live plants for a 5-gallon tank

In addition, plants also offer a suitable nesting spot for shy critters. In a 5-gallon tank, you want to choose a small aquatic plant. They are low maintenance! Even a few healthy plants will make a big difference in how stable water quality is kept.

Suitable fish & inverts

Some delightful fish and invertebrates will flourish in a 5-gallon aquarium. Considering that you should only add fauna after the aquarium is mature, the aquarium must be fully cycled before receiving its inhabitants due to the low volume of water and vulnerability to water quality degradation. In a 5-gallon aquarium, it is easy to alter the water’s chemistry which can cause fatality to the inhabitants before you even realize it. When going for Dwarf Crayfish, be sure to pick one of the smaller species, such as Cambarellus diminutus, and not the larger Florida Crayfish (Procambarus alleni). You can quickly put together dwarf shrimp species – like red cherry shrimp – or snails – like nerite snails – in pretty much all of the situations; even if you go for a Betta, it’s an excellent and striking combination.

Popular Stocking Combos For A 5-Gallon Tank

All species in an aquarium tank need to be compatible in good conditions. Generally, it would be best if you aimed to include species without worrying about each other behavior. Here are some different fish that you should consider keeping and combine. Cardinal tetras have torpedo shape bodies and striking blue and red colors. White cloud mountain minnows are named from where they came from. Sparkling gourami is pretty active, swimming all over the tank, mainly in the upper part of the water column. Molly fish, or mollies as they are affectionately known, are another household favorite. Endler’s livebearers are a unique species with a torpedo body but with a large and colorful fin. The chili rasbora is considered a nano fish, only reaching approximately 0.7 inches. The best fish in a 5-gallon tank should plan for low flowing water and tons of live vegetation.


Many species are small, averaging 2 inches long; they are usually kept in pairs and bred in small aquariums. It is maintained without problems in the five-gallon aquarium. Trumpet snails are an excellent way to clean debris from tanks. Amano shrimp is a great tank companion. Shrimps and snails are the best way to keep your tank clean of algae and food debris, and they can also eat fish eggs. Some species of killies can be aggressive to each other and other fish.

Guppies (Poecilia reticulata)

A tank stocked with only two male guppies will cause a rush of competition when feeding them. Try to keep a small group of females and fewer males. The problem is that a 5-gallon tank will rapidly fill with fry guppies. Guppies are much more intense and energetic than betta fish and are ideal for fishkeepers who want to see fish swimming around the glass with excitement for the next meal or anything else. Male guppies come in various colors and shapes, from colorful redtails to panda-colored. It would be best if you kept female and male guppies in clumps without violence. Get more information from our Guppy article!

Cherry Shrimp (Neocaridina davidi)

Unlike fish, cherry shrimp do not excrete too much bioload, and thus they don’t generate much waste. So with 10cherry shrimps in a 5-gallon tank, you will not be dealing with ammonia spikes caused by the same number of fish that would probably create. Cherry shrimp flourish in the same conditions & care in the same ways as bettas and guppies and are harder animals and easy to keep than you thought. No RO water or special salts for shrimp are necessary. Use conditioned tap water for water changes in the cherry shrimp tanks. They are the perfect species for beginner aquarists and expert fishkeepers who are adventuring into nano fish tanks.

Corydoras Pygmy

Corydoras, corys, or cory-catfish are small tropical freshwater catfish that live in shallow waters. They prefer to be in schools, and 5g / meter tanks don’t provide much space for many Corydoras species, but some are dwarf or pygmy species that you can keep inside nano tanks. A sponge filter is perfect for a small fish as these filters prefer less water flow. These cute animals look fun as they slide around your tank. They make a great addition to any planted tank and can be one of the best fish for a 5-gallon tank if you keep their water quality and avoid overfeeding.

Fish to avoid

Some fish are often recommended as suitable for five-gallon tanks while doing much better in a larger tank. They’re too active, grow too big, and cannot cope with water instability. Try to study each species you want to keep and use good sense when stocking such small tanks. Even some species of Rasboras, which are always listed as great fish for small aquariums, require more than 5 gallons to thrive. The same happens with some species of Gouramis, even if they are dwarfs.

Fish you shouldn’t keep in a 5-gallon tank.

Fish that do not accept tanks prone to suddenly changing the water parameters shouldn’t be kept in a 5-gallon tank. Angelfish are big-sized fish to be held in any nano tanks, but even if marked as juveniles, they will not survive because of the stress. Oscar fish and similar-sized cichlids will soon outgrow a 5-gallon tank and have a hard time as juveniles because they’re very active and territorial fish. Almost all kinds of catfish, cichlids, barbs, and many tetras and livebearers are far from thriving and merely surviving in those small systems.

Fish not to have in a 5-gallon tank

Goldfish and Carps are large size fish and great waste producers, which makes the perfect mix to crash the system of a five-gallon container. Dwarf cichlids can fight to the death if kept together or get super stressed if left alone; in such a small space. Other species of cichlids are terrible residents, as they grew large and are highly active and aggressive. Loaches are out of the question, even dwarf ones because they need water with a fast flow and excellent quality. Virtually any fish that grows beyond 1 inch, is aggressive, territorial, or lives in huge schools are impractical to be kept at this tank size.

Why should I buy a 5-gallon tank?

Nano tanks can be easily installed under counters, desks, or any other place, and naturally, it costs a lot less money. However, a 5-gallon fishing tank can have some severe cons too. It limits the number and types of species and inverts to be housed in it. Larger tanks allow you to stock schooling fish best kept in groups of at least six individuals. They need open spaces to hide from stressors or relax for them swimming in the water.

Keep in mind…

How to design and maintain a perfect nano tank? Tell yourselves about what is best for the fish species that you want to keep. Remember, understocking is always better than overstocking, and choosing a safe population can avoid many troubles over time.

Safety in numbers?

Several species are shoaling fish that become highly stressed and fragile if not kept in teams of six to five individuals. Tiny animals are particularly vulnerable to stress when kept alone or even together. In nature, a large shoal of nano fish looks a lot safer than living alone or accompanied by one partner. Find out here if the fish you are considering buying meets your requirements and is suitable for a 5-gal tank.

What do you think?

We hope that what you learn from this article has been beneficial. Remember always test your water constantly, understand the variation of parameters on your nano, carry out scheduled maintenance, and keep an eye on your animals and plants; this way, you can prevent almost all significant problems that major aquarists face.


A 5-gallon tank is used for those who want to be challenged. Putting too many fish in one place can quickly result in the collapse of the tanks and the death of the fish and inverts. If you want to create a vibrant ecosystem, consider buying a 5-gallon aquarium and filling it with plants and understock with fauna. The rewards for small tanks are derived from the effort and concern we put into them. The compensation for an aquarist is due to our hard work and effort in the tank.

[Must Read] Best Fish For a 20-gallon Tank (With Pictures )

[Must Read] Best Fish For a 20-gallon Tank (With Pictures )

Embarking on a journey into the world of aquariums? Explore our guide to discover the best fish for a 20-gallon tank, ensuring a thriving and balanced aquatic ecosystem.

There are a lot of freshwater fish species kept as pets for people across the globe. This type of animal is fairly more economical than other small animals and does not require much maintenance.

A 20-gallon tank is an interesting aquarium size for a novice hobbyist and the more experienced ones. It provides an excellent volume for the care of several species besides occupying little space.

Factors That Influence How Many Fish You Can Keep In 20 days.

The idea of 1 inch of fish per gallon is a bit old and useless. When stocking a 20-gallon tank, you got to be accurate; the tank configuration will influence the number of fish you can keep.

If you want to have multiple species in your aquarium, other factors may come in. A good selection of fish and tank companions is the best choice for any aquarium.

Make sure the animals you are keeping together have the same preference for water conditions.

How many fishes in a 20-gallon tank?

There are various types of species that can be kept in a 20-gallon fish tank. In this article, I’ll present some freshwater fish and stocking ideas for your 20-gallon tank that you can apply or customize for your setup.

How many fish can be in a 20-gallon fish tank?

A 20-gallon fish tank has a lovely size for keeping some fish but stay away from overpopulating it. Too many fish will cause stress and water deterioration, resulting in sick, strained fish.

How many fish can you keep in a 20-gallon tank?

You should be able to fit around 15-20 small fish for a 20-gallon tank. A goldfish can overgrow, so these kinds of fish are not for this size of the tank.

How many fish can a 20-gallon tank hold?

Usually, people think of a certain number if they’re tempted to keep a certain quantity of fish from their tank. Instead, make sure to spend time researching the fish you plan to keep.

Learn their needs and temperament and try to figure out how they fit together with tank mates. This is especially important when you’re trying to select the right fish for 20-gallon tanks.

During your research, you will also need to consider the different parts of your tank. Some fish occupy the upper part of the water column, some in the center and others in the bottom.

How many fish for a 20-gallon aquarium, stocking ideas

A container of 20-gallon water has 20 1-inch fish per gallon of water. Remind yourself that the length of fish described in this article will be the maximum length you can comfortably keep in a 20-gallon tank with the best environment and the proper maintenance.

Big fish for your 20-gallon tank

If you have a big fish in your tank, I suggest thinking about buying a larger tank. Those are fish which you should avoid.

Best fish for stocking a 20-gallon tank – ideas & combinations

A 20-gallon tank is a mid-size tank, so you’d want to be careful what fish you fish and what type to keep. The best fish we have found for a 20-gallon aquarium is the fish you can keep in small low-tech tanks.

Which fish is best for a 20-gallon tank, and how many can you fit

A 20-gallon tank is ideal for a beginning enthusiast because it offers plenty of options of fish to choose from. You can keep all sorts of aquatic fish and plants. We give you some of the most excellent fish you can keep in your 20-gallon tank in this guide.

Guidelines for stocking your 20-gallon tank

However, in some aquariums, owners overstock their tanks often. It can be considered certain factors for measuring safe stocking levels.


Generally speaking, your guideline for stocking your aquariums is about its filtration system and common sense about physical space for fauna to swim, hide and have a peaceful corner in the aquarium. For this, perform tests to assess the aquarium’s water quality, know the efficiency of filtration, and find out if your aquarium is full of fish.

Stocking your freshwater aquarium

A 20-gallon aquarium allows you to keep many live plants and various beautiful freshwater fish, and exciting animals. I listed some of the most fantastic fish for a 20-gallon tropical tank. Every fish, critter, plant, and decoration in a tank play a role in the health of the aquarium. The goal of making these micro-ecosystems is to build one that requires as little effort as possible to keep going.


Livebearers are freshwater creatures who give birth to tiny fry. These fishes may be the most commonly encountered within an aquarium, with most coming from the family Poeciliidae.

It includes guppies, mollies, swordtail, platys, and others. One benefit of keeping livebearers is that they’re easily bred. There are many species where the males fight each other when trying to mate.


Bettas are slow-swimming fish. They most often swim on the top of the tank. Shrimp can also live with betta fish, but you have to provide them with hiding places not to become a meal for the fish.

Siamese Fighting Fish can thrive in a 20-gallon aquarium. Choose peaceful but quick-moving fish for tank partners; avoid fin nippers.


Neon tetra fish are most widely used for aquarium fishing. Tetras generally have tiny, compressed, and brightly colored bodies. Other than Neon Tetra, Black Neon Tetra can also do well in 20-gallon tanks.

They’re easy to rear. It’s best to keep them in schools of at least six fish. Other tetra species include the Rummynose Tetra, the Black Phantom Tetra, and the Glowing Light Tetra. Tetras can make an essential part of the aquarium.


You can keep dwarf cichlids in a 20-gallon tank. Angelfish, Discus, and other cichlid grow pretty massive and rapidly to be held in a 20-gallon tank. Dwarves can get territorial during the breeding process. It is not uncommon to keep Rams and Apistos in these sizes of tanks.

Dwarf Gourami

Dwarf gouramis are the only fish in this list I’d consider semi-aggressive. In general, they are mostly peaceful and can offer superb communities fishing.

If there are two, they can fight, or you may bully either partner. To reduce the chance that this happens, try to avoid using two males in the same tank. It is also a good idea to provide an area in your aquarium so that a bullied animal can hide.

Can you list the best fish combinations for a 20-gallon tank?

In general, when filling your 20-gallon tank, try to have one or two bigger “centerpiece” fish and fill the rest with a class of smaller fish and a few bottom dwellers like snail or shrimp.

In general, twenty-gallon tanks should be a perfect size for a novice tank owner. And always remember that it’s crucial to understand the nitrogen cycle and how to maintain healthy water conditions for your fish.


Zebra Danios are exceptionally active fish that generally stay in the upper areas of an aquarium. They are native to South Asia and rely on a large tank because they love swimming and chasing other fish.

Other Danios can be kept in 20 gallons of tanks, including Danio Marginatus, Pearl Danio, and Celestial Pearl Danio. These fish can also fight with other fish, such as guppies and others, so be aware when stocking up your aquarium. The danios zebras are happier in groups with five to six fish.

Best fish for a 20-gallon tank


Swordtail’s appearance is almost the same as those of platies. In an aquarium situation, you need a male for every two females. It reduces the stress on the female when the males start harassing them.

Best fish for a 20-gallon tank


Aquarium shrimp can add a fun element to your aquarium as they come in multiple sizes and colors. They also molt as they grow that inevitably makes them shed exoskeletons. They are scavengers who eat anything, including animals and plants (dead or alive).

Best fish for a 20-gallon tank


Otos are cute little shoaling fish that go into glasses into a 20-gallon tank. They are little plecos that remain small, and you can keep a small group in a tiny tank. You might want to enhance his diet with algae wafers. The fish are the best algae eaters for small tanks.

Best fish for a 20-gallon tank


Barbs usually live in schools in soft, acidic water. Most barbs are fin nibblers and don’t like long-finned fish. Barbs can even kill other fish. They are a very active type of fish.

Best fish for a 20-gallon tank


Rasboras are possibly the best kind of fish for small community tanks. These fish also originate from freshwater habitats in Southeast and South Asia. Due to their peaceful nature, they are excellent tankmates. Also, these fish shows unique breeding and shoaling habits, all with fantastic color. These examples of common Rasbora species regularly held in aquariums are Red-Lined, Pygmy and Harlequin.

Best fish for a 20-gallon tank


Cory catfish are an excellent addition to any tank. They will eat leftover fish foods that get lost in the tank. They’re big-bodied schooling fish.

Best fish for a 20-gallon tank

Tell me the biggest fish you can put in a 20-g bag?

You want to keep fish less than 6 inches in size. Fish has to have space in the tank to swimming and also relaxing. Avoid keeping large numbers of fish in a small tank.

Additional factors

Any extra addition to the tank will reduce the amount of space that is available to the fish. Plants and gravel could also impede the flow of water in the tank.

Always add filtration and aeration. But you shouldn’t rely too much on such aid, as any blackout will be disastrous; keep an eye open.

Fish You Shouldn’t Keep In A 20-gallon tank.

There is also lots of fish that should never be kept in a 20 gallons tank. It’s not acceptable to fill tanks with large cichlid or other large fish.

Angelfish are territorial species that have a semi-aggressive temperament and can kill smaller fish. In addition, Common plecos grow faster even as juveniles as they can occupy all the tiny tanks in a short time.

Goldfish can die prematurely in small aquariums.

Best live plants for a 20-gallon tank

Planting Vallisneria in your 20-gallon tank is the best way to turn your nano aquarium into an aquatic jungle. Amazon’s Sword is a good option for nano tanks.

Sagittaria dwarf has a grass-like appearance. A lot of Wisteria species can make excellent places of cresting for fish. It flourishes with liquids or tablets of fertilizers and tends to take over the underwater landscape as it can propagate via side shoots. It is easy to take care of.

Size considerations

Many times the fish bought in the pet store are youngsters that will grow more. Check the average size of each fish when mature, and use this measurement to figure how much space the fish need. It’s not unusual for a fish to double in size pretty quickly.

Specific needs

Most fast swimmers need more area than slow swimmers, even though they tend to be active all the time. You’d better give your fish plenty of room to eat, which helps protect the peace by decreasing the number of unpleasant encounters.

Some large fish will produce more waste than much smaller fish and can alter your storage capacity or tank filtering ability as well, when in a 20-gallon tank.

Lights for a 20-gallon tank

Lighting is critical to fish to maintain the day and night cycle. Although there are plenty of lights available, it is better to turn off their tanks at night. Adjust in the minimum of 12 hour light and 12-hour dark.

Fish tank filtering system in a 20-gallon tank

That filter is the critical component in every tank. Filters keep good bacteria and make sure to keep the water free from pollutants for longer. The best the filter system, the healthier the fish, and the less maintenance is needed.

20-gallon tank water heater

A simple water heater offers a better quality of life to the 20-gallon fish tank residents. The heater is essential to keep the temperature stable; the fluctuation of this parameter and others can cause a drop in the fish’s immune system, causing diseases and other pathologies present in the tank to appear. It’s easy to set up a thermometer when looking for a quick and easy way to monitor the temperature.

The last step is adding water.

Once you have assembled the basic structure with the tank, heater, filter, lighting, plants, logs, and other decorations, it’s time to fill it with water.

Depending on the substrate you use, the water can get murky the first time you fill the tank, and you might have to wait for patience till the debris settles in.

If you add some fish to your new tank – without cycling it – you’ll have to perform numerous water changes; otherwise, you will have a big ammonia problem. Before adding fish, keep your tank going (while full of water) for 2 to 4 weeks for the bacteria to attach themselves to your filter so that they can carry out the nitrogen cycle and be able to maintain a good quality of water in your aquarium.

Good luck with your aquarium!

A 20-gallon aquarium includes stocking options outside of its 10,000-gallon capacity. If you want big fish or many fish, you will probably be better off getting a 55-gallon tank or bigger.

Or if you’re going to set up a small community with some beautiful fish and maybe some excellent plant, having one this size will probably suffice. This article is not meant to supplement diagnosis, prognosis, treatment, prescription, or a qualified veterinarian’s formal guidance.

Final thoughts

A 20-gallon tank is a perfect aquarium for any beginner. It provides a chance to care for different animals without taking too much space. Always ensure to keep track of the size of the fish species when stocking.

In any case, ensure it is the right environment for the species of your choice. Set up and decorate the aquarium correctly with a heater, filter, plants, and everything else you want.

Remember to make space available for the animals to swim, hide and rest whenever they want. Use common sense when populating the tank, and know the habits of the fish you want to keep; this will help you choose which area of the aquarium to occupy.

Keep your maintenance routine up to date, keeping your water always in perfect condition; that way, you shouldn’t have any problems.