What Fish Are Best Suited For Very Small Aquariums?

-- By Carol

Seeing all the large fish tanks will often make you wonder what fish are best suited for very small aquariums.

It is common to see small fish tanks in the market which are usually more affordable.

However, if you don’t know what kind of fish you should keep in them, it can be disastrous.

People tend to make this mistake pretty often – they get a small fish tank and either add too many fish or keep the wrong species in the tank.

You can either have overcrowding issues or just have fish that keep dying in your small aquariums.

This can be discouraging and most people often give up because they failed to properly look after their small tank.

That’s why it is a good idea to properly research what fish are best suited for small aquariums beforehand.

There are also other areas that you should research. To make sure that you don’t have any problems, we will help you out.

So, if you are looking forward to keeping fish in a small aquarium, the following is one major factor you should consider before you get them.

Table of Contents

How Small is a Very Small Aquarium?

Before you start shopping for fish, you need to consider the water capacity of your small aquarium.

In short, you need to work out how small your very small aquarium is. A good small aquarium should be able to hold 5 gallons of water.

Do not believe the false marketing behind 1 gallon or even 2-gallon fish tanks. These are not perfect for fish or for use as community fish tanks.

At the most, these tanks can be used to house freshly bred fry or as shrimp tanks and water plant tanks.

Keeping fish in a 1 or 2-gallon tank isn’t a good idea. They don’t have enough room to swim and will generally die off soon.

The poor betta fish is often the victim of these tanks because it is said that they can survive in small tanks.

The keyword here is to survive.

Betta can live in these tanks but to truly thrive, they need a minimum of 5 gallons. The same is said for many other small fish species. They do better in more space even if they can live in smaller tanks.

Additionally, you will find 5-gallon tanks classified as nano-fish tanks. Anything above 10 gallons is a medium-sized fish tank and anything above 20 enters the realm of large.

So, when you are picking out a nano-tank, stick to 5 gallons or even 8 gallons.

What Fishes are Best Suited for Very Small Aquariums – 5 Gallon Water Tanks

Once you understand the challenges of a small aquarium, it is time to consider the inhabitants of the tank.

Not all fish species do well in small tanks so you might find that your options might be a bit limited.

If you are wondering what fish are best suited for very small aquariums, we have the answer for you.

The following are some fish species that do well in small aquariums.

As a special bonus, most of them are brightly colored species that will make your tank look breathtaking:

Siamese Fighting Fish – Betta Splendens

Fish Size – 2.6 inches (6.5 cm)
Recommended Tank size – 5 gallons or more
Water Temperature – 75° to 85° F (23.8° to 27.2° C)
pH Range – 6.5 to 7.5

These beautiful fish are loved because of their amazing scales. Male betta fish are brightly colored and will flare their fins when threatened or startled.

Due to their aggressive nature, male betta fish must always be kept alone. Females can be kept in sororities of 4 or 5 without any problems.

They aren’t suited as community fish although some people have had success keeping them with cory fishes.

They do well in planted tanks with plenty of hiding spaces. Avoid fake plants as their delicate fins can get cut in aquarium tanks.

They do best when given live food in their diet.

Dwarf Rasboras – Boraras Maculatus

Fish Size – 1 inch (2.54 cm)
Recommended Tank size – 5 gallons or more
Water Temperature – 73.4° to 80.6° F (23° to 27° C)
pH Range – 4.7 to 6.2

The bright color of dwarf rasboras makes them a must-have for any tank.

The males have a vibrant ruby red hue which makes them very noticeable in a tank.

They do best when kept in schools of 5 or 6 gallons. Without enough fish, they tend to hide and get stressed out.

While a generally hardy fish, they are timid and can become stressed easily, especially if housed with aggressive tank mates.

They enjoy plenty of hiding spots and like live plants in large chunks. Lighting should be kept minimal as they do not like a lot of light.

Pygmy Sunfish – Gulf Coast – Elassoma Gilberti

Fish Size – 1 inch (2.54 cm)
Recommended Tank size – 5 gallons or more
Water Temperature – 68° to 74.3° F (20° to 23.5° C)
pH Range – 6.5 to 7.5

These are other types of small fish that have a stunning appearance. You will be hard-pressed to find a prettier fish than these.

The males tend to color up and flare their fins when they are claiming their territory in the tank.

Due to their territorial nature, it is not a good fish to keep with timid fish species.

They enjoy calmer waters and tend to require dense vegetation in the aquarium. Additionally, they like to eat live food and will thrive best when given a steady diet of insects and micro-worms.

However, in a 5-gallon tank, you should house no more than 2 pygmy sunfish. If you want to add some tank mates, consider getting a bigger tank of at least 20 gallons as these fish like their space.

Dario Dario – Badis Bengalensis

Fish Size – 0.78 inch (2 cm)
Recommended Tank size – 5 gallons or more
Water Temperature – 68° to 78.8° F (20° to 26° C)
pH Range – 6.8 to 7.8

Another vibrantly colored fish species, the Dario Dario is an exotic freshwater fish that can be a bit difficult to find.

This fish is usually found in a red-orange color and the males are more brightly colored.

Some of the males can get territorial and aggressive but this temperament isn’t seen in all the males.

They like sandy floors as these mimic their natural habitat. For hiding spots, they are happiest in coconut shells.

The Dario Dario will flourish when kept alone in tanks. They tend to fight with others for food, space, and even mates.

They can also prey on other fish so smaller tank mates aren’t a good idea with them.

Guppy – Poecilia Reticulata

Fish Size – 1.25 inches (4.8 cm)
Recommended Tank size – 5 gallons or more
Water Temperature – 72° to 82° F (22° to 28° C)
pH Range – 6.8 to 7.8

Available in a number of different colors and tail types, the guppy is the favorite of many beginners. This fish is extremely attractive.

They are the most peaceful fishes you can find and you can keep them with other tank mates. These are community fish and thrive best with other guppies.

In a 5 gallon tank, you should keep a minimum of 3 guppies. Additionally, it is a good idea to keep 2 females with 1 male.

Otherwise, males can start to compete and become aggressive. This can also help you get started with breeding your own guppies.

Ember Tetra – Hyphessobrycon Amandae

Fish Size – 0.7 inches (1.7 cm)
Recommended Tank size – 5 gallons or more
Water Temperature – 71.6° to 83.3° F (22° to 28.5° C)
pH Range – 5 to 7

These are some of the coolest, smallest fish you can add to the tank. Their small size makes them naturally form schools for protection.

They are red in color and are extremely attractive to look at. They are happiest in calm water and when kept in groups to allow them to shoal and swim around.

For maximum comfort, make sure you keep at least 5 or 6 ember tetras together. Smaller groups can leave them feeling stressed out and timid.

They do well in community tanks with non-aggressive tank mates. They thrive well in an aquarium that has driftwood, logs, and plenty of plants for them to hide in.

These are our top recommendations of fish that are best suited for very small aquariums.

You might find other options as well but always remember to keep the welfare of the fish and other tank mates in mind when you are picking the fish for your aquarium.

The Challenges of Keeping a Small Aquarium

Another thing you need to consider is that keeping a small aquarium is more challenging than keeping a large one.

The following are some common challenges that you will face with them:

More Maintenance

Did you know that small aquariums require more maintenance? In fact, the larger the tank is, the more control you actually have over the water parameters.

Once you are dealing with water tanks that are below 10 gallons, the maintenance and care the tank needs increase.

Difficult to Maintain Water Parameters

Maintaining the pH, the nitrates, nitrites, and maintaining oxygen levels are more challenging with small tanks.

You also have to do more frequent water changes, monitor water levels, and watch out for overcrowding.

The smaller the tank is, the quicker it will become polluted by the fish.

The constant fluctuation in pH can also stress fish out or make sensitive ones become prone to disease. This can be lethal for the tank’s inhabitants.

More Expensive

Most people opt for small tanks because they believe that these are cheaper.

While the initial costs for small water tanks definitely seem less, the smaller tank is far more expensive than a larger tank in the long run.

The equipment you need is also more expensive for tanks that are smaller than 10 gallons.

A lot of the time, the cost of equipment for a small water tank is such that you actually end up paying more for them than what you would for larger tanks.

Lack of Space in the Aquarium

Aquarium equipment is not always available in a mini-size for small tanks.

This means that your already small tank will become crammed with a filter, water heater, and thermometer in it.

The lack of swimming space has also been known to cause aggression in fish.

When a fish feels confined, it will become aggressive and more territorial. Keeping tank mates with aggressive fish is not a good idea as they will get bullied or worse, killed by the angry fish.

Easy to Overcrowd

With large tanks, you can get away with adding two or three different species and building a community tank to view.

However, that is not the case with small tanks. The smaller space limits the number of fish you can keep.

With some territorial species, you might only get to keep one fish in the small tank.

Smaller fish might also do better as part of a school which means that you will have to get 3 or 4 of the same fish.

Even allowing for the fish to school can cause overcrowding. You can unwittingly add too many of the same fish which can make the tank become crammed.

Not Meant for Beginners

Given the level of difficulty that comes with maintaining small water tanks, these are definitely not recommended for beginners.

In fact, beginners should get larger tanks ranging from 15 to 30 gallons.

These are easier to maintain, can be used as community tanks, and will generally give your fish a healthier environment.

So, if you’re looking for a fish tank, avoid getting smaller ones and opt for something larger.

However, if you know what you are doing and are confident that you can manage a small one without harming the fish, then get a nano-tank today!

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