If you want to start an aquarium with very limited space, a 5-gallon tank is your ideal size. Small as it may seem, there are still plenty of things you can do with this size, as long as you do things right – like choosing the best fish for a 5-gallon tank.
Luckily, you’ve got options. Some of the best fish species include Bettas, Guppies, Mollies, Endler’s Livebearers, Least Killifish, Celestial Pearl Danio, White Cloud Mountain Minnow, Sparkling Gourami, and Pygmy Corydoras.
In this article, we’ll discuss the best fish for a 5-gallon tank!
Best Fish For A 5 Gallon Tank
|Size||2 to 4 inches|
|Number in 5-Gallon Tank||1|
|Lifespan||2 to 5 years|
|Temperature||78°-80°F or 25.5°- 26.5°C|
|pH||6.5 to 7.5|
Also known as Siamese Fighting Fishes, Bettas are a fan favorite when it comes to small tank setups.
In fact, if you’re fine with just a lone fish in your nano tank, a Betta is a perfect choice.
The males of this colorful species are extremely territorial, and most will attack other fishes, including their own.
Thus, Bettas do best when they’re alone in their tanks, or perhaps with one or two invertebrates with them.
They’re also pretty hardy. Although we should strive to keep our tanks pristine, Bettas can tolerate a wider variety of water parameters than most aquarium fishes.
This hardiness makes them suitable for small setups, where tiny changes to the water quality can affect all inhabitants.
Aside from that, they’re also not very picky with their food. With their omnivorous diet, you can feed them flakes, live food, frozen food, and everything else in between.
Beginners will love choosing Betta fishes for their 5-gallon tank. This species has tons of varieties – from coloration, fin, and even shape.
Their personalities are also very enjoyable. Each fish has its own personality, and they tend to be very active explorers.
There’s plenty to love in such a small fish, but don’t worry, it will fit perfectly inside a 5-gallon tank. Just ensure that it’s properly outfitted with the necessary equipment, like heaters and filters.
|Scientific Name||Poecilia reticulata|
|Size||0.6 to 2 inches|
|Number in 5-Gallon Tank||3 males, or 2 females|
|Temperature||72°-82°F or 22°-28°C|
|pH||7.0 to 8.0|
Guppies are some of the most widely distributed fishes in the hobby. If you’ve ever seen an aquarium, then you’ve also most likely seen a bunch of Guppies somewhere.
These lively little fishes are also favorites for small tank setups.
For one, they’re a peaceful species. Males can typically coexist with each other, and although you might find an individual a little more aggressive than the others, you won’t find them fighting to the point of death, unlike Bettas.
They’re very active fishes, too, so you’ll enjoy watching them swim around in your tank the whole day.
Like Bettas, Guppies also come in a wide variety of types. They can be differentiated by color, tail shape, size, and even shape – with some rare varieties priced higher than even other fish species.
Luckily, as long as their fundamental needs are met, Guppies will thrive in a five-gallon tank.
That said, keep in mind that raising Guppies in such a small area can come with a few caveats.
For one, some types of Guppies need to be part of a school to be really comfortable. This means that you need to keep multiple of them, or they’ll suffer. Therefore, they won’t do well in a five-gallon tank.
Another factor to be wary of is how fast Guppies can breed.
Since they’re livebearers, you have to be careful of female Guppies. Some aquarium owners have experienced getting a female Guppy that turned out to be in the early stages of pregnancy.
If you’re planning to keep your Guppies in a five-gallon tank, you need to make sure that all of them are the same sex and that none are pregnant prior to arriving, or your tank can very easily be overrun.
|Scientific Name||Poecilia sphenops|
|Size||3 to 4 inches|
|Number in 5-Gallon Tank||1 or 2|
|Lifespan||3 to 5 years|
|Temperature||72°-78°F or 22°-28°C|
|pH||7.0 to 8.0|
Mollies are also popular, beginner-friendly fishes that you can raise in a five-gallon setup. Mollies and Guppies belong in the same Family (Poecilia), so it’s not surprising for them to share many similarities.
In addition, Mollies have many different types and varieties. They can also give birth to live young and can easily overrun your tank if you’re not careful enough. Even aspects like diet, temperament, and life span are quite similar to Mollies.
Perhaps the only thing where they differ is in appearance and size. While Guppies have a delicate body and flaring fins and tail, Mollies have a thicker body with smaller fins.
They can also generally grow about one inch more than the average Guppy in length. Thus, you should only keep just about one or two male Mollies in a setup of that size.
As mentioned, caring for Mollies is pretty straightforward. As long as you take the proper precautions and have the right water parameters, your Mollies will thrive in a 5-gallon tank.
|Scientific Name||Poecilia wingei|
|Size||0.75 to 1.25 inches|
|Number in 5-Gallon Tank||4 to 5|
|Lifespan||3 – 5 years|
|Temperature||75-85°F or 24-29°C|
|pH||7.0 to 7.5|
Endler’s Livebearers can be mistaken for Guppies as well – so much so that they’re often called Endler Guppies, even though they’re not the same species.
Guppies and Endler’s Livebearers have a similar size and coloration to Guppies, although they do have a few key differences.
For one, Endler’s Livebearers often grow significantly smaller than Guppies. Guppies can have a maximum size of 2 inches, while Endlers can only attain 1.5 inches in maximum.
Endler’s Livebearers also tend to have a reflective neon or silver coloration and shiny, iridescent scales.
While Guppies can have reflective coloration, they tend to be more on the flat, vivid side of the scale.
Nevertheless, if you’re looking for the best fish for a 5-gallon tank, these fishes are also a good choice.
However, you need to follow the same precautions when taking care of Guppies and Mollies. If you don’t want an overrun tank, make sure that they’re all the same sex, as these species breed very fast.
|Scientific Name||Trigonostigma heteromorpha|
|Number in 5-Gallon Tank||3 to 5|
|Lifespan||2 to 3 years|
|Temperature||73-82°F or 23-28°C|
|pH||6.0 to 7.8|
Harlequin Rasboras are also one of the best fishes to have in a five-gallon setup. These hardy fishes are lively and full of personality, and they have a unique pattern that makes them stand out.
Their name comes from their coloration; the pattern of the black scales on their body is reminiscent of red and black suits, which earned them the moniker of ‘harlequins.’
They’re also a very hardy species.
As you can see from the chart above, they can tolerate a wide variety of temperatures, and they’re not very sensitive to changes in the water – ideal traits for a small tank setup.
However, we’re going to bump up the caring difficulty of these fishes because of the complications of keeping them in a small tank.
This is because harlequin rasboras are schooling fishes; they live in large groups of 5 above. Because of their size, having a school of five fishes in a five-gallon tank can be challenging to pull off, but it can be done if your tank is expertly planted and properly filtered.
Thus, you need to have an experienced aquarist to keep a school of this species in a five-gallon setup – but when you do, you’ll find that they’re very rewarding to take care of.
|Scientific Name||Heterandria formosa|
|Number in 5-Gallon Tank||2 to 3|
|Temperature||68-80°F or 20-27°C|
|pH||6.0 to 7.0|
The Least Killifish, also known as the Mosquito Fish, is another fish belonging to the livebearer family – the same one that Guppies, Mollies, and Ender’s livebearers belong to.
These tiny fishes look very similar to Endler’s Livebearers, although they tend to have more neutral colors. Beginner aquarists will love their hardiness and personality.
They’re very active explorers, and they will want to look around their new five-gallon home, so make sure to keep some plants or decorations. They’re also quite hardy and tolerant of a wide range of aquarium temperatures and water changes.
The same precautions apply to the Least Killifish as when keeping other livebearers: be wary of keeping females or a male-female pair, as they breed like crazy.
However, you should also keep in mind that males of the same species tend to fight to establish dominance. If keeping more than one male in a tank, you would do well to have plenty of hiding spaces like plants or driftwood.
Celestial Pearl Danio
|Scientific Name||Danio margaritatus|
|Number in 5-Gallon Tank||3 to 5|
|Temperature||68°-78°F or 22°-26°C|
|pH||6.5 to 7.5|
Celestial Pearl Danios were only discovered in the past decade, making them relatively new to the aquarium hobby.
However, they are already growing in popularity because of their attractive appearance and interesting nature.
These fishes have interesting patterns in their body. They have dark blue or black scales with many white dots on their body that earn them their name – their white dots look like shining pearls in the night sky.
These are shy and timid fishes, and they require several things to thrive, upping the difficulty of keeping them.
For one, their natural habitat is densely planted, shallow bodies of water. If you want your Celestial Pearl Danios to live happily, then you should mimic this habitat, which means that you need to have a very densely planted tank.
Plus, you also need to keep them in a school of about five or more.
If you want to keep them in a five-gallon tank, you’re going to require expert care and balance. You need to juggle the plant density, swimming space, and shoaling numbers together in a tightrope exhibition.
If you’re experienced and knowledgeable enough to pull it off, though, keeping them will definitely be a celestial experience.
White Cloud Mountain Minnow
|Scientific Name||Tanichthys albonubes|
|Number in 5-Gallon Tank||3 to 5|
|Lifespan||3 to 5 years|
|Temperature||58°-72°F or 14°-22°C|
|pH||6.8 to 7.5|
White Cloud Mountain Minnows got their name from their pretty silver coloration. These beautiful fishes often sport greenish or cloudy white scales in their body, with a thick black line bordered by a brighter pink running through their body. They also have peripheral colorations of red and blue.
Additionally, they’re peaceful fish. They don’t fight among each other and tolerate a wide variety of tankmates in their home.
Aside from their active and lovable personalities, beginner aquarists will love their hardiness, as these are one of those fishes that don’t need a heater in their tanks.
White Cloud Mountain Minnows are perfectly happy in temperatures ranging from 58°F to 72°. While they are happy in pH levels of 6.8 to 7.5, they can also tolerate pH between 6.0 and 8.5 for some time.
However, you do need to maintain a five-gallon tank in pristine conditions if you want to have them. These fishes are shoaling fishes, so if you want to keep them in a nano setup, you need to ensure that the water is very thoroughly filtered and they have plenty of open areas to swim.
|Scientific Name||Trichopsis pumila|
|Number in 5-Gallon Tank||2 to 3|
|Lifespan||3 years or more|
|Temperature||76°-82°F or 24°-27°C|
|pH||6.5 to 7.0|
Although most Gouramis variants typically grow too large for a simple 5-gallon setup, the Sparkling Gourami is one type that you can safely keep in a five-gallon setup.
These fishes are some of the smallest varieties of Gouramis around, only growing to about 1.5 inches in maximum length. They have interesting coloration that can shine iridescently when under direct light, which is also where they got their name from.
Sparkling Gouramis are not schooling fishes, so you can safely keep just 3 of them in a tank this size. In fact, it’s not recommended to have more than this since the space can become too crowded for them.
However, do note that the males of this species can be quite aggressive. They will harass other fishes, so it’s best to keep only one male in the tank and two females to divide their attention.
They also prefer a heavily planted home, so caring for these bumps up the difficulty level a bit as you have to take care of plants too.
That said, keep in mind that this Gourami species can be quite delicate. You have to make sure that the water parameters are always ideal for them, or they will suffer stress or develop an illness.
Aside from those precautions, though, Sparkling Gouramis are definitely a joy to keep. Their interesting, individual personalities and beautiful coloration can bring a much-needed spark of brightness to a tank filled with greenery.
|Scientific Name||Corydoras pygmaeus|
|Number in 5-Gallon Tank||3 to 5|
|Temperature||73°-79°F or 23°-26°C|
|pH||6.0 to 7.5|
Pygmy Corydoras are another classic in the US aquarium scene. These are tranquil little bottom-dwellers that don’t grow too large – perfect for a five-gallon nano setup as long as you do the proper maintenance required.
Pygmy Corys belong in a family of catfishes, and you can see it in their down-turned shape. They have defined scales and an interesting coloration of metallic black and white stripes running down their body.
These bottom-dwelling fishes prefer to graze and zoom around on the aquarium substrate and glass. However, they do appreciate fairly dense foliage as well.
Thus, you need to ensure that they have plenty of surface area to explore. You can still keep a densely-planted aquarium, provided they still have a bit of substrate to explore.
Moreover, Pygmy Corydoras are schooling fishes.
In addition to their somewhat delicate nature, these factors mean that you need to be extra careful in designing and equipping a five-gallon tank for a sustainable Cory school.
Best Stocking Combinations For A 5 Gallon Tank
Stocking a five-gallon tank requires extreme care and balance.
This is because small tank setups are particularly prone to water upsets. Since there’s only a small volume of water, changes in water parameters are easily felt throughout the whole tank. It means that you need to be very mindful of waste and filtration.
Aside from that crucial factor, you also need to consider swimming levels and feeding zones. This is the area of the tank where a fish might spend most of their time looking for food.
The levels are as follows:
- The area of the aquarium nearest to the surface. Fishes like White Cloud Mountain Minnows and Guppies spend plenty of time swimming in this region.
- Fishes like Rasboras and Gouramis spend most of their time exploring the mid-section of the tank.
- Pygmy Corydoras spend most of their time grazing through the aquarium’s substrate for food.
Knowing your fishes’ swimming levels is crucial in a five-gallon tank because you want to maximize the space. You can’t do this if fishes run into each other in the same aquarium area; thus, if you plan to get multiple species, you need to get different ones for differing levels.
For example, here are a few stocking combinations you might want to look at.
- Top: Killifish or Guppies. Bottom: Pygmy corydoras.
- Top: Mollies. Middle: Rasboras.
You can also keep invertebrates like shrimp or snails in a 5-gallon tank.
However, you’re going to be pretty limited by the size of your tank and the bioload it can carry, so be very mindful about stocking multiple species in your tank.
How Many Fish Can Be In A 5 Gallon Tank?
The general rule of thumb is to keep a one-inch length of fish per one gallon of water volume. So, if you want to know how many fish can be in a 5-gallon tank, the simple answer is that you can only keep about five 1-inch sized fishes or two 2-inch ones.
That said, this is only a very rough guide and doesn’t consider other crucial factors such as the following.
- Some fishes (like male Bettas) won’t tolerate other fishes in their territory, so you need to give them the entire tank even if they’re relatively small.
- Social needs. To be happy in a five-gallon tank, some fishes need to have at least four other companions of the same species.
- Breeding tendencies. Fishes like Guppies, Mollies, and other livebearers breed very promiscuously, so you need to keep their numbers very low in advance.
Thus, answering how many fishes can be kept in a five-gallon setup can’t be so straightforward, as you have to consider various factors of the fish species you want to keep.
Fish To Avoid Putting In A 5 Gallon Tank
You might have already noticed based on this list that not all species are suitable for a 5-gallon tank. This means that there are also fishes that you must avoid putting in a tank of this size.
This section will discuss the fish species you shouldn’t house in a five-gallon aquarium.
This goes without saying, but fishes that can grow too large can’t be put in a five-gallon tank.
And no, this doesn’t just mean that you can have one five-inch-sized fish and call it a day. Individual fishes that can grow to that size will most likely need plenty more swimming area, plus all the other factors discussed in the previous sections, so it’s best to get a larger tank.
Fishes that produce plenty of waste will easily overload your 5-gallon system and are best left out of the equation altogether. This is especially true for Goldfish and others of their kind.
Many shoaling/schooling fishes such as Neon Tetras and Common Danios might fit in a five-gallon tank individually, but they need to be with their school to feel safe.
Plus, fishes like these tend to be very active swimmers, and they’re bound to want plenty more swimming area than what a five-gallon tank can offer.
You might also have noticed that we added a few shoaling fishes to this list. This is because you can certainly pull off putting a minimal school of small fishes, such as some Guppies, Celestial Pearl Danios, and other small species.
However, it takes a considerable amount of mastery to pull it off, so beginner aquarists are not advised not to try it.
A single Betta will do wonderfully in a five-gallon tank, but it’s not the same for all territorial fishes.
For example, Angelfishes are highly territorial even while juveniles, yet they need to belong in a group.
Fishes like this need plenty of space to establish their territories so that they won’t fight, so even if you can fit their size in a five-gallon (which is unlikely anyway), you best not do it.
We’ve already discussed that beginners should avoid putting fragile fishes in a small tank because they can easily feel even small changes in the water parameters.
This is true even for fishes listed in this article, such as Pygmy Corydoras. However, careful aquarists can still give these fishes a great home.
Equipment For A 5-Gallon Tank
5-gallon tanks don’t need plenty to get started. They only really need four pieces of equipment – although you do need to monitor the water parameters constantly.
Here’s a list of what you need in your 5-gallon tank:
- Nano-tanks with built-in filters like the Tetra 5-Gallon Aquarium Kit and the Fluval SPEC 5-Gallon Aquarium Kit are great options.
- If there’s no built-in filter, you can use a basic sponge filter, such as Xinyou’s Sponge Filter.
- You’ll need aquarium lights like Aqueon’s Clip-On LED Light to see your fishes clearly, and if you’re keeping plants, they also need adequate lighting to grow.
- If you want to keep tropical fish like Bettas, you need a heater, such as the Marineland Precision Heater or the Tetra HT Submersible Heater to keep the water temperature constant.
Take note, live bacteria are essential for your five-gallon tank’s filtration, so you can use something like the API Quickstart Nitrifying Bacteria to establish a colony much faster in your nano tank.
Keeping aquarium fish is an exciting and fulfilling hobby that everyone can get into – even those with little space in their homes.
Nano tanks with five gallons of volume are ideal for this purpose, as long as you equip them properly and are diligent in performing maintenance. You also need to choose the best fish for a 5-gallon tank for them to thrive in their new homes.
With this article, now you know the best options you have for your tank!
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