5 Best Fish for 5-Gallon Aquariums

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Setting up a 5-gallon tank can be a challenge. There is not much space to work with and you have to be careful which fish you put together in order to not disturb the ecosystem of the aquarium.

It is easy to overstock a 5-gallon tank if you are a beginner or if you don’t have the correct information. If they are overstocked, they can become very dirty quickly. That will only cause you the unnecessary trouble of maintenance.

You also need to consider what type of fish you put into the tank. First of all, the fish need to fit together in terms of character. An aggressive fish will disturb the feeding patterns of the more peaceful fish, which will make it harder for the peaceful fish to live in your tank.

Another consideration for you is the size of the fish. Make sure that the fish are not too big for a 5-gallon aquarium. Make your research before buying the fish.

Some fish may grow larger than what you would expect, and that would make them unsuitable for a 5-gallon tank. You can also put snails and shrimp into the tank.

In this article, we will take a look at the best fish you can consider buying for a 5-gallon tank.

How to Stock a 5-Gallon Fish Tank?

When stocking a 5-gallon fish tank, you have to consider how many fish you put into the tank and how big the fish will be when they are fully grown. Here are some suggestions on how you could set up a 5-gallon fish tank.

1. Betta Fish (1 fish)


Betta Fish

The Betta fish are very popular for smaller tanks. As a species, they tend to be very aggressive towards other fish in the tank, especially towards other betta fish males.

That is why it is best to keep one betta fish in your tank alone. Their other name tells you everything – they are also called the Siamese fighting fish.

But having a betta fish is worth it. They are very beautiful and their appearance is unique. It originates from Southeast Asia and it is accustomed to flooded rice plains and is quite adaptable due to many floods in that area.

They have adapted so that they can survive out of the water for short periods of time. They have the ability to breathe oxygen from the air.

As for the diet of the betta fish, they like to eat bloodworms or shrimp, but they will also eat dry food. They prefer slightly acidic water (pH of 6.5-7). Make sure that the water is clean as well.

2. Guppies (2 females + 1 male)


Guppy Fish

Guppies are one of the most popular fish for small tanks, both for beginners and advanced aquarium enthusiasts.

They are very small, as they only grow to about 1.25 inches (3cm), so they are perfect for smaller aquariums.

What makes them so popular is that they are very peaceful, colorful and they are also quite cheap. Guppies are also very active.

They move around the aquarium a lot and they make for a very pleasant sight. They love a dense setting with plenty of vegetation.

Guppies are community fish, so keeping one guppy alone would not be an option. They prefer to live in groups, so my recommendation for a set up with guppies is to put 2 female guppies with a male.

They will not coexist well with a more aggressive fish, so keeping more guppies together would be ideal; a 2:1 ratio between females and males would work best. This setup is also good if you want to breed your own guppies.

3. Ember Tetra (5-6 fish)


Ember Tetra (sourceCC BY-SA 4.0)

Tetra fish are a very good option for a 5-gallon tank. They are community fish, so they prefer to live in groups. For a 5-gallon tank, having 5 or 6 ember tetra is my recommendation. These fish are very small, as they only grow to about 0.7 inches (1.7cm).

They are peaceful and will happily co-exist with other peaceful fish too. The Ember tetra is glowing orange, which makes it one of the most attractive species for a 5-gallon tank.

It is native to Central Brazil, which is a highly forested area with plenty of greenery, so it has adapted to that – they like aquariums with plenty of greenery and roots, as they are very active and will move around quite a lot.

What also makes them a popular choice among aquarists is the fact that they are low-maintenance. You obviously have to clean and filter the water, but the ember tetra is not picky when it comes to food. They like to eat live food, but they will happily eat dried foods too.

4. Endler Guppies (3 females + 2 males)


Endler Guppy

Endler guppy, or Endler’s livebearers, are close relatives to the guppy fish. They are tiny fish that are one of the most popular fish species for smaller tanks.

The males of the endler guppy grow to about an inch (2.5cm), while the females tend to grow larger – up to 1.4 inches (3.5cm).

Having more Endler’s livebearers in your tank can make for fireworks. With their colorful body and quick movement, they are one of the most popular choices for a 5-gallon tank.

They like tanks that are thick in vegetation and with small pebbles or grain on the bottom.

Like some other species on this list, the Endler guppies are also very easy to care for. They like pH neutral water that is about room temperature.

In terms of food, the Endler guppies are omnivores – they will eat everything from live food to dried foods. I recommend that you put more females than males in the tank, as the males will haunt the females if there are more males in the tank.

5. Sparkling Gouramis (3 fish)


Sparkling Gourami

The sparkling gouramis are a bit unique; they are rarely found in home aquaria and their appearance is also unique. The clue is in the name –  they are very bright and colorful. It grows to about 1.5 inches (3.8cm), which makes them perfect for a nano aquarium.

As for the stocking, I recommend that you put 3 sparkling gouramis into a 5-gallon tank for best results. This will make sure that they will have enough space.

They like light aquariums with plenty of vegetation and slow water flow. Regarding their diet, they too like to feed on dried and live foods. So they are easy to care for and very attractive, which makes sparkling gouramis a good choice for your 5-gallon tank.

Setting Up a 5-Gallon Tank

Setting up a small aquarium shouldn’t be hard. You don’t need to spend a lot of money to create a good looking and healthy ecosystem. Though, there are few things to consider when setting up a mini aquarium.

1. Good Filtration

The first thing you will need to do when setting up your 5-gallon tank is to set up a good filtration. In some cases, a filter might come with the aquarium starter pack. If not, you must buy one. Make sure that you choose the right filter for the fish you have in your tank.

If you have betta fish, for example, make sure you buy a gentle filter that will enable the fish to swim in the water easily. If the filter is too strong, it will disable the fish to move freely in the aquarium.

Having good filtration in your tank is very important, as it will help keep the water clean and it will keep the water flowing. When the filter fills up, it is necessary for you to clean it on a regular basis to keep it working properly.

Good filtration is essential for a good setup.

2. Fast Growing Plants

When choosing the plants for your 5-gallon aquarium, it is important to consider how these plants will fit into your aquarium. You want to have a good looking aquarium? Then it is important that you choose the right plants for it. Not only the plants will make the aquarium look good, but they will also allow the fish to hide.

In the right conditions, the plants will grow fast and then you will need to either replace those plants with smaller ones or keep them inside. Some of the best plants for a 5-gallon tank include Java moss, Amazon sword, Anubias Nana, Java Fern. There is plenty of interesting choice.

3. Gravel Substrate

Next, you will need to choose the right gravel substrate for your tank. Like plants, gravel on the bottom of the tank is important to have as it makes the fish feel more at home, and it also allows them to hide in it.

Ideally, it is good to have 3 inches of gravel on the bottom. This will prevent the bacteria from growing. As for what substrate to choose, it depends on personal preference and on the fish in your aquarium. The most common choices are gravel and sand.

4. Lights

Another important aspect for your aquarium is the lighting. This aspect of aquarium setup is often overlooked, especially by beginners. But it is very important, especially if you have some fish that are more accustomed to lighter environments. Not only that, but it will also light up your aquarium and it will make it more attractive – you will be able to see more colors.

Also, consider which fish you have in your tank. For freshwater fish, it is normally a good idea to have some more lighting. For swamp fish, a dimmer setting would be better.

Maintaining a 5-Gallon Nano Aquarium

It is really cool to have a small aquarium on your office desk or in your room, but how do you keep it healthy? Here are few tips on how to maintain and keep a 5-gallon nano fish tank in good shape:

1. Regular Water Changes

You want to test your water regularly. If the water tests are bad, you want to change the water regularly, rather than putting more chemicals in it. You have to change the water in your tank frequently – ideally on a weekly basis. You do it by taking about a third of the water out of the tank and then replace it by clean, fresh water.

If you do not do this, the water will become dirty and it will become very uncomfortable for the fish in it. Besides filtering the water, this is the best choice for cleaning the water. But you have to do it constantly in order to get rid of unwanted chemicals and to neutralize the pH of the water.

2. Gravel Vacuuming

To avoid having more debris and filth in your water, it is important that you vacuum your gravel on the bottom. You can do this by using a siphon. First unplug the filter and the heaters, if you have them. Then put a bucket underneath your vacuum and start vacuuming. Put all the dirty water into the bucket.

This method will enable your water to stay clean and prevent debris and filth from accumulating in and beneath the gravel.

3. Plant Trimming

Trimming your plants in the aquarium is important if you do not want to have too big plants in your tank. You want to monitor the size of the plants in the aquarium and then if they have grown too much, simply trim them and keep them in check. Not only will this improve the look of the tank, but it will also enable more space for the fish in the tank.

You will have to trim stem plants most often.

4. Filter Cleaning

As mentioned above, it is important that you clean the filter of the aquarium on a regular basis. The filth and debris that is collected in the filter will cause the filter to become ineffective and as a result, the water will not be filtered properly. So make sure that you clean your filter constantly for best results.


Small 5-gallon aquariums are very difficult to get right, but when you do it, it is a very satisfying thing when you start to see results. A good 5-gallon aquarium starts with choosing the right fish for it. Some of the best options are the betta fish if you want a lone fish, guppies, endler guppies, sparkling gouramis or the ember tetra.

Any fish you choose, you will have to also consider the equipment suitable for the fish, but most importantly, you will have to maintain the tank on a regular basis.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.

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