A 5 gallon tank, often considered a “nano tank” by some aquarists, does not offer a lot of space to work with—but that doesn’t mean you can’t create a fascinating ecosystem. If you are a beginner without much experience in fishkeeping, a 5 gallon tank can be both a blessing and a challenge, especially when it comes to choosing the best fish for a 5 gallon tank.

So, if you want to know which fish is the best for a 5 gallon tank, you have come to the right place. Choosing the right fish is important when you have a small aquarium, because you want a species that is not just going to survive but thrive in the space it has. There are many kinds of fish that need a lot of swimming space and will quickly become depressed and sick when kept in cramped conditions.

Therefore, knowing which fish enjoy smaller spaces or who do well alone is key to ensuring your aquarium not only looks beautiful but supports life.

The Best Fish For 5 Gallon Tanks

Let’s have a look at the best options of fish for 5 gallon tanks. These fish (as well as invertebrates and amphibians) are all known to be hardy and forgiving in terms of mistakes with water parameters, so you can learn how to maintain a small tank without risking too much. Be sure to note the special conditions required for each option, however, since that increases their happiness and health.

1. Endler’s Guppies (or Endler’s Livebearers)


Source: Azgarden.com

Some guides will tell you that you can add 2 males and 1 female to your 5 gallon tank, but this is a mistake. Guppies are sometimes called the Million fish, because they can reproduce at an extraordinary rate, meaning your 5 gallon tank can rapidly become overcrowded if you are not careful. Choose only male guppies for your 5 gallon tank, allowing you to get 3-4 of them, since they are generally smaller and more narrow than females.

2. Mexican Dwarf Crayfish


There are a number of invertebrates that you can add to your 5 gallon tank—cherry shrimp, amano shrimp, ghost shrimp, fry, and snails—but none of them are like the Mexican dwarf crayfish. This species of crayfish is peaceful and docile, so it won’t spend every waking moment trying to flee the confines of its aquarium. You can add a single Mexican dwarf crayfish to your 5 gallon tank as a partner to other docile fish.

Note that you can only keep one dwarf crayfish at a time, because they will be defenseless during molting season and could come under attack from other invertebrates or even more aggressive fish. Keep them well feed on a vast diet of bloodworms, mosquito larvae, peas, and fish pellets.

3. Betta Fish

betta fish

Originating from Cambodia and Thailand (hence the other name, Siamese fighting fish), betta fish are a delightful addition to any tank. They can be feisty and aggressive, making them ideal for solitary settings or mixed in with tetras, danio, or even a guppy or two. Otherwise, they do not need tank mates and are beautiful and colorful enough to brighten any aquarium by themselves.

Betta fish often need a filtered, heated, and landscaped tank to be happy, however; so if you can’t provide that, it may be better to get guppies or danio or something similar. Betta fish also like tranquility and standard substrate. Give them plenty of shrimp or bloodworms. Keep the water slightly acidic (around 6.5-7.0 pH level).

4. Ember Tetras


Source: Manzanita-driftwood.com

You may have heard of neon tetras, but have you ever seen ember tetras? These fiery orange fish do astoundingly well in smaller tanks and bowls and are very resilient. The only thing you have to do is keep them in groups to ensure maximum happiness and health. Like all tetras, ember tetras are schooling fish and will require around 5-6 fish in a 5 gallon tank to display their full personality.

These fish are native to the jungles of Brazil, so your tank’s decorations should reflect that. Add plenty of live greenery with dangling roots, such as red root floaters, and make sure they have a decent spectrum of food options.

5. Sparkling Gouramis


The sparkling gourami is a unique looking fish that you rarely see in aquariums, because they can be difficult to find. These brightly colored fish look like they are glittering when caught in light, so they are bound to be a beautiful addition to your tank. And since they grow to a max of 1.5 inches (3.8 cm) long, you can keep 2-3 of them in a 5 gallon aquarium without issues.

Sparkling gouramis require well-lit tanks, slow water flow, and a good amount of vegetation. They are omnivorous but like a blend of different foods. Otherwise, they are very easy to care for.

6. Least Killifish


Do you want more than 1 or 2 fish in your 5 gallon tank? Then you should consider least killifish, a native of North America. Males grow to about 0.8 inches long, and females reach about 1.2 inches. Hardy, they can survive in water with pH levels ranging from 6.5 to 8.0. All you need is plenty of plant life, decent lighting, and decent filtration.

However, because least killifish are the smallest freshwater fish in North America, they are not ideal for keeping with bigger fish, since they can easily become the food source in the tank. Only keep them with other killifish.

7. Dwarf Puffer (Pea Pufferfish)

fish tank sand

In the past, you would have never considered a tiny freshwater pufferfish being on a best fish for 5 gallon tank list—but here we are! Dwarf puffers, sometimes called pea pufferfish or pygmy pufferfish) come from Southwest India. They are, however, not recommended for beginners, because they are demanding and require precise conditions. You must keep the water quality warm and all minerals in check.

Also, pufferfish are more carnivorous than most additions on this list and can be finicky, only accepting food when they want it. You can keep a pair of dwarf puffers in a 5 gallon tank along with live plants and substrate, since they like hiding together.

8. White Cloud Mountain Minnows


Source: Azgardens.com

Found in freshwater sources throughout China, these minnows grow to about 1.5 inches in length and feature red caudal fins and slightly green scales. The males are brighter than the females. You cannot keep white cloud mountain minnows alone, however, because they will become stressed, lose their vibrant coloring, and spend most of their time out of sight.

Also, these minnows do not like too much heat. Their ideal water temperature is 64-68 degrees F (18-20 degrees C), and they like darker colored substrate, rocks, wood, and a few plants. To ensure their health, give them plenty of food choices, like crisps, daphnia, free-dried worms, and flakes. Also, if you have males and females, you should keep a lid on the aquarium, since males will chase the females so much they opt to fly out of the tank.

Also, pufferfish are more carnivorous than most additions on this list and can be finicky, only accepting food when they want it. You can keep a pair of dwarf puffers in a 5 gallon tank along with live plants and substrate, since they like hiding together.

9. African Dwarf Frog


Okay, so, while the last option is not a fish by any means, but an amphibian, that doesn’t mean you should rule out the African dwarf frog, because it is as forgiving of mistakes as any aquarium pet could be. Alone or paired with another frog, they will forage for food, often trying to put anything into their mouths that they can find, or wrestle playfully with their mates. Put a spot of dry land in the tank for them.

However, African dwarf frogs also have terrible eyesight and, thus, cannot be paired with small fish and snails, since they will be seen as food. You can put a couple of African dwarf frogs in a 5 gallon tank to keep them happy. They are also adaptable to temperature and pH levels, but the ideal is around 72-78 degrees F (22-26 degrees C) with a pH of 6.5-7.8.

How To Set Up A 5 Gallon Tank For Your Fish

Now that you have seen some of the best fish for 5 gallon tank, you can now figure out how you are going to set up said tank. There is more to caring for fish than giving them water and food. You want an attractive ecosystem, too.

Here are some things to consider:


Depending on the type of fish you want, like a betta fish, you will need a good filter. If you buy a starter park, it will most likely come with a decent filter. However, if the filter is too strong, the water flow will become unfavorable, since your fish will have difficulty swimming. Choose a filter that does not disrupt water flow all that much.


Choose the right kind of plants for your aquarium. Some may grow too slow to be beneficial, while others may grow too fast and require a lot more maintenance than you planned on. The best plants for a 5 gallon tank include Amazon sword, Java fern, Anubias nana, and Java moss.


Next, you need to choose a sand or gravel substrate. This makes the tank feel more like home to your fish, especially if you have bottom feeders. Try to have around 3 inches of substrate at the bottom of the tank to prevent bacteria from growing.


Another essential aspect of a great tank is the lighting. Don’t overlook the need for a great light. Most fish are accustomed to bright environments, and it can help warm the water, too.


The last thing you need to consider is how much maintenance is required for a 5 gallon tank. Since you have less water, you will need to conduct routine water changes instead of adding chemicals. Measure the pH and other levels of the water throughout the week, too. The less water you have in a tank, the more quickly it can become unbalanced with ammonia and nitrates.

You will also need to change the substrate once in a while, trim the plants, clean the filter of debris, and keep a careful watch on the temperature.


Although 5 gallon tanks can be challenging to figure out in the beginning, you can quickly master the aquarium and make it a happy home for your fish. The best fish for a 5 gallon tank is one that will adapt to the conditions and doesn’t grow too big. Luckily, there are plenty of choices for stocking a 5 gallon tank, including brightly colored betta fish and fascinating invertebrates. Whatever fish you choose, make sure you have the right equipment and time.

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