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7 Best Fish for 1 Gallon Tank (Complete Guide)

7 Best Fish for 1 Gallon Tank (Complete Guide)

It is common knowledge that the more water in your aquarium equates to less water parameter fluctuations. While it is usually better to have more water than less, some hobbyists choose to have a smaller aquarium due to its minimalistic nature and challenges involved. 

Although it can be a challenge to maintain such an aquarium, it is still very possible if done so very carefully. With the proper precautions, a small tank might even be more successful than a larger one. 

In the sections below, we cover some options for recommended 1-gallon tanks and some options for fish as well!

Recommend 1 Gallon Fish Tank:

Ideally, fish keeping revolves around trying to minimize water parameter fluctuations. The bigger the tank, the lesser the fluctuations because there is more water to buffer. 

Fishes thrive in environments that are stable and thus most hobbyists try their best to keep parameter fluctuations at bay either through robust filtration systems, meticulous maintenance routines, a larger volume of water, or sometimes all of the above. 

Imagine dropping a drop of red paint into a glass of water, the resultant effect would be the water tainted red. Now imagine dropping that same drop of water into a pail of water, would the red now be less or more intense than the drop of red in the glass? The red in the glass would be more intense of course!

Similarly in a fish tank, excess nutrients build up much quicker in a smaller environment as compared to a larger one. 

However, with proper maintenance and meticulous care, some keepers still have reported successes with keeping some fish in small 1 gallon tanks. Again, this is not something we recommend, however, it is possible. 

Listed below are some fish that would be suitable for this type of tank. 

  1. Guppies
  2. Betta
  3. NeonTetra
  4. Endler’s Live Bearers
  5. Zebra Danio
  6. White Cloud Minnows
  7. Dwarf Spotted Danios

Best Fish for 1 Gallon Tanks

Keeping fish in a one-gallon tank may seem easier to manage than with larger tanks, simply because of the size. Although it does have its perks, it might actually prove to be even more difficult. 

Many beginners usually prefer to start small, to not go beyond their initial capabilities. And sometimes this proves to be a big mistake as beginners are not equipped with the skills needed to maintain fish in such a small environment.

The most important thing to note when keeping a small tank is to always be one step ahead. What this means is to always be prepared for something to go south, and quickly. 

It is also very important to choose livestock that is hardy enough and can withstand a certain amount of parameter fluctuations. 

1. Guppies

guppies tank

Guppies are one species of fish that you can keep in a small tank. You’ll notice that most of the fishes we’ve listed above are fishes that are exceptionally small and relatively hardy. 

Guppies are a good choice because they are a small species that have proven over time that they can survive tough conditions. While this does not necessarily mean we intend to torture the guppies, having them live in a small tank can be rather stressful.

Thankfully, guppies do great because they generally don’t eat as much and don’t grow big. But you should note that you will not be able to house more than a pair of guppies in a 1-gallon tank. 

The more guppies you house in a 1-gallon tank, the more likely the tank will crash and your guppies with it. Keeping a small tank clean will require more effort than with a larger tank – as it gets contaminated with waste matter very quickly. It is therefore highly recommended to have a water filter.

2. Bettas 


Bettas are one of the hardiest species of fishes around. Fit for both beginners and experts, Betts generally require little care. 

It is entirely possible to keep a Betta in a 1-gallon aquarium. In fact, quite a number of hobbyists who own multiple Bettas choose to keep them in a smaller aquarium because they do very well in smaller spaces, let us explain why. 

Bettas belong to a group of fish that possess a very special breathing apparatus called the labyrinth organ. This special organ enables them to take in oxygen from the surface above. 

They evolved to have such organs because of the environment in which they originate from, where most of the waters are usually stagnant and have a low oxygen content. 

That said, however, they still require a certain level of care and should never be allowed to live in squalid conditions even though they might survive. 

Bettas however are extremely territorial fishes and should never be housed together. Another common name for them is the ‘fighting fish’. They are called that for good reason because males will fight to the death if put in close proximity of another male. 

They are also very disease resistant and can survive a wide range of water parameters, but that docent means you should neglect your maintenance schedule. With proper care, the Betta is a wonderful fish to keep with a load of personality to boot. 

3. Neon Tetras

neon tetras lifespan

Neon Tetras are a small species of fish that originate from South America. Amongst all the fishes we talk about today, they will be one of the toughest to maintain in a 1-gallon tank. 

The reason for the Neon Tetra in this list is mainly due to their size. Growing to a maximum of about 1 inch, they are a tiny fish that do not require much maintenance. 

But wait, didn’t we mention that they are tough to maintain? Well yes, they are tough to maintain because of their sensitivity to parameter fluctuations. 

However, if you have a robust filtration system and ensure a consistent maintenance schedule, they will do fine! Neon Tetras do not require any special care and should be housed in groups of 3 or more, due to their nature as schooling fish. 

If you do intend to keep Neon Tetras in a small 1-gallon tank, make sure that you have no less than 3 fishes in the tank. That said, small tanks while challenging, can be a great choice for fish keepers looking for a ‘next level’ project.

4. Endlers Live Bearers

Endler’s Livebearer

A close relative of the guppy, the Endlers Live Bearer is slightly smaller in size and has almost the exact requirements as a guppy. 

They are a group of small fish that are not only hardy but beautiful as well. Growing to a maximum of 1.2 inches, this tiny fish is a great choice for keepers who would like to have a small aquarium. 

This species however is slightly more aggressive than guppies and males tend to nip at other males. Females tend to grow slightly larger and can be kept together with males in the same tank. 

We recommend keeping a maximum of 3 of these fishes in a small 1-gallon tank to prevent overcrowding. Even though they are a peaceful species most of the time, having too many in a small space will cause stress and a spike in the bioload. 

They are also easy to feed and will consume almost any commercially available fish food. 

5. Zebra Danios

Zebra Danio

The Zebra Danio is a small fish that looks like its name suggests, a zebra. Albeit they have horizontal stripes, the Zebra Danio is another good choice for a fish in a small tank. 

Growing to a maximum of 1.2 inches, the Zebra Danio is a great choice as they are both hardy and easy to keep fishes. 

Zebra Danios are active fishes that are also easy to feed and most commercially available food will be sufficient for them. In a small tank, it will be wise to feed your fishes sparingly as overfeeding will cause a quick buildup of excess nutrients that will eventually kill your fish. 

Do note, Zebra Danios are relatively prolific breeders. Although it is unlikely to happen in a small aquarium, there is still a chance, hence it will be best to keep them in tanks of opposite sexes. 

Overall, the Zebra Danio is very easy to keep and will thrive if consistent maintenance is carried out. 

6. White Cloud Minnows

White cloud mountain minnow

White Cloud Minnows have long been a great beginner fish to start with. Their hardiness and size make them one of the best starter fishes to begin with. 

Unlike the Neon Tetra, White Cloud Minnows are hardier and can withstand parameter fluctuations better than most other small schooling fish. Apart from their sensitivity to copper medication, they will withstand most novice mistakes. 

Growing to a maximum of 1.5 inches, they are a small fish and great for smaller tank sizes. Hence they make an excellent choice for a 1-gallon tank. 

However, it is imperative that you keep no more than 3 of these fishes in a 1-gallon tank as overcrowding will add to the bioload and cause massive fluctuations in water parameters. 

7. Dwarf Spotted Danios

Danio nigrofasciatus

The Dwarf Spotted Danio is closely related to the Zebra Danio and has almost identical care requirements. The biggest difference between them is their size!

Growing to a maximum of 1 inch, the Dwarf Spotted Danio is a hardy and easy to keep species that require little care. You will realize that almost all fishes in this list grow to a maximum of 1.5 inches. 

Having small fishes in a small tank will drastically increase your chances of success as small fishes tend to have a lower bioload as compared to larger fish. 

As they are a schooling fish, the Dwarf Spotted Danio should be housed with others of the same species. However, due to the small tank size, we recommend no more than 3 fishes in a 1-gallon tank. 


In the section below we try to answer some of the commonly asked questions that people ask about small tanks. 

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

Generally, the rule of thumb is to have 1 inch of fish per gallon of water in your tank. That means that if your fish is 3 inches, the minimum amount of water you should have for that fish alone should be 3 gallons. 

However, due to the circumstances, we’ve seen much success with people keeping groups of small fishes in very small tanks. As such, our recommendation for a small tank would be with one slightly larger fish (like a Betta) or 2-3 smaller fish like tetras. 

That said, keeping them in a small tank is easy, consistently maintaining the tank is not. Smaller tanks will require a more rigorous maintenance schedule due to the sheer levels of parameter fluctuations. 

The smaller the tank, the more the parameters will fluctuate. Hence we generally do not recommend small tanks, especially for beginners. 

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

Like we said earlier, the maximum number of fishes in a small 1-gallon tank would be 3. This is because, even though they are small fish, having too many in a small space will create problems. 

Again, small volumes of water have big fluctuations. But not just that, small spaces will create overcrowding issues that will stress your fish, further reducing your chances of success should you decide to have a small tank. 

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

Goldfishes are large fishes by all accounts. They are not recommended to be kept in a 1-gallon tank. 

Although it is common to see goldfishes kept in a bowl, it is very cruel and ultimately will kill the goldfish. While some keepers have success with keeping them in small tanks, a one-gallon tank is definitely out of the question. 

Goldfish have voracious appetites and produce a lot of waste. Keeping them in a small one-gallon tank is a spell for disaster. 

Oh did we mention, they sometimes grow up to 12 inches in length too! Doesn’t sound like they’d be comfortable in a one-gallon tank does it? 

Closing Thoughts

Keeping a small one-gallon tank is both challenging and rewarding at the same time. While it is not recommended for beginners, we know many keepers who specialize in keeping small tanks like these, and they do so to great success. 

The key point to take away from this article is that the small the volume of water, the larger the fluctuations. These fluctuations can come in the form of temperature, pH, excess nutrients, or even oxygen levels. 

Fishes generally don’t do well with parameter fluctuations because their bodies are not designed to do so. The same can be said of humans, imagine you’re in the Sahara desert for a minute and in Antarctica for the next. I don’t think we’d survive long in such an environment, same goes for fishes. 

We hope you’ve enjoyed this article as much as we have put it together. Do leave us questions and comments in the section below!


Sunday 26th of July 2020

My child a batta at a school event we got a on gallon tank for it and has been happy for 8 months now. We couldnt aford a big tank at the time and didn't really have the time to envest in a bigger one than that. I also didnt want my my kid to cry about it dying and a 1 gallon tank is much better then the little cup it came in. I only have one plant in it a very small one but its seems pretty happy to me my kid changes the water 2 times a week so she is learning responsibility also.

daniel fard

Friday 22nd of May 2020

a one-gallon tank is too small for any fish betta fish needs at least a 2.5-gallon tank and goldfish need at least a 20 gallon for one. you couldn't even keep shrimp in a 1-gallon tank.

Saurabh Kumar

Friday 22nd of May 2020

I completely agree with you! But this is just a helpful post for those who have limited space and want to explore the hobby, and in most cases, a 1-gallon tank is a temporary solution!

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