10 Best Fish for 1 Gallon Tank (Complete Guide)

Best 1 Gallon Fish

Every aquarium requires a good amount of water in the tank, because, obviously, most fishes require lots of water to thrive. It is thus often recommended to have a tank capacity that can hold a few gallons of water.

Besides, more fishes in the aquarium requires more water, and so water seems to be a key requirement in maintaining your aquarium. However if you are constrained on the amount of water you can provide, yet you still want to keep a fish, well  all hope is not lost.

However the ideal environment for fish keeping requires you to have ample space for the fish to roam about effortlessly, which should be ideally much more than a one gallon tank.

This is thus why many seasoned aquarists assert for a larger fish tank. But of course, if you are meticulous about giving all the required care for a one gallon fish tank, then it is possible to successfully do so. Interestingly, there are a number of fishes you can keep that can do fine in a one gallon tank.

Some fishes that can be successfully kept in a one-gallon tank include;

  • Guppies
  • Bettas
  • Tetras
  • Goldfish
  • Paradise Fish
  • Endler’s Livebearers
  • Zebra Danios
  • White Cloud Minnows
  • Dwarf spotted danios
  • Glowlight tetra

Best Fish for 1 Gallon Tank

Keeping a fish in a one gallon tank may seem easier to manage, because of the smallness, however it does have its perks and might prove even more difficult. Many beginners usually prefer to start small so as to not go beyond the initial capacity.

But then, in keeping a one gallon tank, you must have a precise way of managing the fish in it. Depending on the fish you choose to have, knowing how to care for them is very important.


Guppies are one specie of fish you can keep in a one-gallon fish tank. Looking at the physical features of guppies, they are very small and even when fully matured, can comfortably stay in a one gallon tank.

guppy fish

It is, however, better to keep a guppy fry in such a small tank and not a matured one.  They however require good water conditions and would not survive in unclean water.

Thus, a one-gallon tank would need to be frequently replaced for a guppy. It might be really more of an effort to keep the tank clean because it gets contaminated with waste matter very quickly.

Being a schooling fish, staying alone is quite bad for them. But considering that they are in a small tank, you might keep two or three, under the strictest care, to keep them healthy and happy.

They are a quite friendly species and are not likely to harm one another. It is highly necessary to have a water filter in this type of condition.


Keeping a betta fish in a one gallon tank is possible, but this doesn’t guarantee that it would be the best conditions for it. Bettas are however very hardy and can stay in uncomfortable water conditions.

Betta Fish Flaring

They also have a labyrinth organ which requires them to come up for air often. This allows them to survive in a poorly oxygenated water condition, as they can get some oxygen from the atmosphere.

Thus, they would find it easy to come up easily in a small tank. In any case, you need to be careful about keeping bettas in such conditions.

It would be possible to keep only one betta in such a small tank. Having more than one would be very unhealthy and the fish wouldn’t survive

Paradise Fish:

For a one gallon tank, a paradise fish is a fairly good option. This is because it can survive in several water conditions ranging from comfortable to not-so-comfortable.

They are also easy t care for, and are not fussy eaters. Thus, they are usually preferred by fish keeping hobbyists who are new to the activity.

It is important to ensure the hygiene and health of the fish is closely monitored. You would be required to check daily for stress, for unhappiness or tiredness in the fish.

White Cloud Minnows

This is another kind of fish that can comfortably stay in a one gallon tank. This is because they are especially easy to take care of and they remain really small. Being about one inch only, they do very well in a small tank.

As long as they are kept in a planted tank, with good feeding and in a small group of three to form a school, they do really well. Many beginners like this choice because they remain happy and are quite hardy.

They are freshwater fish and do not give any trouble if they are in a clean condition. Many people fear that their fish might be suffering malnourishment when they remain small for a long time.

But that is the natural case for the White Cloud Minnows who do not grow large at all and are thus ideal for a small tank.


Almost everyone has come across a goldfish being kept as an accessory in a bowl at home or in an office. While this might actually look pretty, this is definitely not a good state for your fish.

Goldfish Aquarium

Keeping your goldfish in a one gallon tank is however a better option, as there would be a bit more space than what a bowl offers. Also, this would require careful attention in caring for your goldfish. Of course, you cannot keep more than one in a tank this small.

And knowing that goldfish gets really messy and produces even more toxic matter than the average aquarium fish, it would take extra care to ensure that the water tank is kept in the best hygienic condition.

You would also have to be cautious about the diet the goldfish gets. In such a small tank, you wouldn’t want to overfeed your fish. Firstly, this would weigh it down and then it would also accumulate in the tank and further increase the level of contamination.

Many seasoned aquarists would kick against keeping a goldfish in a one gallon tank, but you really can, as a temporary measure for a small goldfish, or if you are just a hobbyist. But still, hobbyist or not, you must ensure the best living condition for any creature, whether in a one gallon tank or not.


Keeping tetras makes you feel like a pretty good expert aquarist. But before you get overexcited in this, you should be careful having them in a one gallon tank. Well, they are cool for a small tank, seeing that they are also a small-sized fish with little trouble.

They are equally very peaceful and can be kept in a little school of three for a one gallon tank. Ensure that the kind of tetra you’re keeping is the small kind, because there are a wide variety of tetras.


Before you get your tetras into a one gallon tank, make sure you confirm from research and from the store the exact nature and features of that specific fish.

Tetras have a variant of characteristics and thus require a seasoned aquarist to care for them. Being a hardy fish, they don’t require any tedious water care besides the regular hygienic care needed for a small fish tank.

Glowlight tetras:

Having a single glowlight tetra in a one gallon fish tank is possible. It is not especially difficult to care for, and may do better in a small school of three.

This is considerable, seeing that they are quite peaceful and friendly, and make good community fish. Being small in size also makes them a good option.

The bright look adds colour to your small tank any day and makes them quite fun to keep. You should however be careful about any tank mates they might have.

Their fins might get nipped at by other active fishes that find them interesting. In essence, you can keep this kind of fish in a one gallon tank on a temporary basis if they are to have a considerably long, healthy life.

Endler’s livebearers:

This specie of fish is quite similar to guppies and are a really good-looking option for your fish. They are also very small in size (about one inch), hence ideal for a small tank such as a one gallon tank.

Endler’s Livebearer

They are peaceful, and not even very popular amongst some aquarists. They come in a variant of colours but cannot be kept in large numbers in a small tank.

Just a small school is required and also a good amount of floating aquatic plants to keep them covered from light. This fish isn’t too demanding when it comes to the right water parameters, and requires a reasonably warm water temperature.

Zebra Danios

This is another good freshwater aquarium fish suitable for a one gallon tank, die to the small size. They are a lovely, beautiful fish to keep, having a zebra-like striped body.


Being active and hardy fish, they can survive an incredible range of water conditions and do not fuss over one special diet. You should however take note that they are active breeders, and being made to breed in such a small tank might be very unsuitable for them.

This means you should not keep matured zebra danios of opposite sex together. In fact the temperature they require does not need you to use a water heater for their tank.

Although you must ensure that you do not have a giant danio instead of a zebra danio. Also, you shouldn’t keep them with aggressive fish, as this might stress them further and shorten their lifespan.

Dwarf spotted danios:

The dwarf spotted danio is even known to be a little smaller than the zebra danio and is hence suitable for a one gallon tank. They are easy to keep, and are quite hardy in several water conditions.

You would have to take note of how well this fish is surviving after a few days, because it might get tired after swimming in a small place for a long time.

This fish looks really nice, but you must be careful to ensure that it doesn’t get contaminated due to toxic matter or waste deposits. Cleaning the water often, as well as having a water filter is an indispensable requirement.

How many fish should you keep in a one gallon fish tank?

The fact remains that a one gallon fish tank is very small. Thus, you shouldn’t have more than one fish in it. It is okay as a starter or just a hobbyist to manage and care for. A single betta would do fine by itself in a tank that small.

A schooling fish, while not recommended can do well in twos or threes, but would be required to be very small fry that would still get a better environment eventually.

Also, avoid keeping fish of opposite sexes, so as to prevent breeding in such an environment. Keeping an aggressive fish in such condition would also trigger more aggression, neither should you put two territorial male fishes in a one gallon tank.

They would get very hostile and one is likely to kill the other. Hence, maintaining a one gallon fish tank is only tolerable when there is only one fish housed in it.

How many tetras should be kept in a one gallon tank?

No more than one fish is ideal for a one-gallon tank. But a schooling fish requires at least two or three if they would be kept happy. As said, it would, however, require more devoted care to keep tetras in such a small fish tank.

How many goldfish should be kept in a one gallon tank?

If you must keep a goldfish in a one gallon tank at all, you must be extra-meticulous. Thus, nothing more than one goldfish is permissible. As said above, they are really messy and they produce a lot of pollution to the water in a short time.

Keeping more than one goldfish in a one gallon tank would be a death sentence, and to ensure the welfare of your goldfish, use a water filter and be religiously and carefully committed to frequent and proper water changes.

How to maintain a one gallon fish tank

While it is true that your fish requires much more space than what a one gallon fish tank offers, it is possible to keep your fish healthy in it if you know the right things to do.

First you must be even much more particular about the hygiene. Because of the small amount of water, waste deposits faster, and a small fish like a goldfish that gets really messy would require cleaning about 2 times a week.

Changing 30-50% of the water every few days, or doing a constant ammonia check is a good way to ensure balance and hygiene.  In fact, your one gallon fish tank really needs to have a small filter assist you in maintaining the hygiene.

Most people who find that they cannot cope with this frequency of maintenance opt for bigger tanks.

Also, you would have to reduce the level and amount of feeding given to a fish in a one gallon tank. It is well known that the more the food, the more the waste produced, and even excess food produces even more waste deposits in the fish tank.

Reducing the feeding to just once in every two days, and in smaller proportions helps to keep the fish tank cleaner and healthier. This is especially good for fishes that are naturally small and grow no more than 1- 1.5 inches upon maturity.

Temperature and lighting

In addition, you must ensure that the temperature, lighting, and pH scale of the water is always balanced. This would reduce the exertion on your fish and would help it conserve energy.

Fish like bettas are quite peaceful and would only get agitated if the conditions of the water get drastically changed. In fact, they like a warmer temperature and would always prefer it to be kept so.

Thus, keeping a betta in a one gallon tank would require you to have the tank within a warm temperature (definitely not outdoors). Also, it is always good to include aquatic plants in your tank.

It would help it get even more oxygenated and give a better semblance to a natural home where the fish can hide and swim about in.

In other words, replacing the water requires you to have checked and adjusted its temperature before introducing into the tank, and ensuring it is well-conditioned.

The water you’re using must be as close as possible to your tank temperature, either by using a heater or by letting the water get adjusted to the same room temperature.

Also, do not forget that the substrates, plants or any decorations need to be cleaned as well, as a lot of waste gets stored amidst them.

Finally, your fishkeeping should not be at the detriment of your fish’s health. Thus while this explains the possibility of keeping different kinds of fishes successfully in a one-gallon tank, you should strive to get your fish in the best living conditions, in bigger tanks and excellent care.

Saurabh Kumar

I am a passionate Fish Keeper, with years of Experience in the Hobby & this is my site. You will find some really useful tips and Information that I learned the Hard way.

Leave a Reply

Your email address will not be published. Required fields are marked *

Recent Content