best fish for a 10 gallon tank

10 Best Fish for a 5-Gallon Tank

A 5-gallon tank is a relatively small fish tank. Therefore, you cannot really use it to stock many fish or big fish. However, that does not mean you have no variety in terms of what you can put in such a tank. There are many types of fish and other aquarium life that you can host in a 5-gallon nano aquarium. In this article, I will share with you the 10 best fish for a 5-gallon tank. 

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But before I share with you the 10 best fish for a 5-gallon tank, here are some important things you need to know before stocking a 5-gallon tank. 

  1. It is widely accepted that you should put no more than one 1-inch fish per gallon. Therefore, for a five-gallon tank, you should put no more than five 1-inch fish. In fact, even five fish for a 5-gallon tank is sometimes considered a bit extreme. This is because such tanks can become toxic fast. Therefore, it is better to have just one or two fish in a 5-gallon tank. 
  2. A 5-gallon tank should only be stocked with fish that grow no more than 1 inch. This is important because any fish species that grow more than 1-inch will need more space to swim and explore. So keeping it in a 5-gallon tank will not really be fair. If you want to stock fish that grow to a bigger size, you should buy a bigger tank. 
  3. It is important to make sure your tank is regularly cleaned to ensure the survival of your fish. As mentioned in the first point, small tanks can become dirty or toxic first. Therefore, to protect your fish, you need to clean your tank regularly. So make sure your tank has a good filter and test the water quality regularly to ensure that the filter is working well.
  4. A five-gallon nano tank is a great option for a beginner aquarist. If you have never had or maintained an aquarium before, you should start small before graduating to bigger tanks. Therefore, it makes sense to buy a nano aquarium. Such a tank will be cheaper and easier to maintain, which is just what you need as a beginning aquarist.

Now that you know everything important you need to know before setting up a 5-gallon fish tank, it is time to discover the 10 best fish for such a tank. Without further ado, here they are. 

10 Best Fish for a 5-Gallon Fish Tank

Below are the fish species that can thrive in a 5-gallon nano aquarium.

1. Betta Fish

betta fish

Betta fish aka Siamese fighting fish are perhaps the most popular small fish species that are kept in home aquariums. They are very territorial fish and are omnivores. Betta fish are just nice to look at. This is because they have got beautiful wings (yes wings not fins) that are colorful and very pleasing to look at especially when they are swimming gently. 

Perhaps the most interesting thing about Betta fish is that they are some of the most intelligent small fish species known to man. In fact, they can learn to identify you and perform some tricks when they see you. They are perfect for putting in a small fish tank because they are small and easy to care for.

A Betta fish can live up to ten years.

2. Dwarf Puffer

Dwarf Puffer 

Dwarf pufferfish are chubby-looking fish that are available in many sizes and colors. They are really nice to look at especially if you get one with a beautiful color pattern and you set up your 5-gallon nano aquarium just right. 

The best thing about pufferfish is that they have very interesting movements and techniques that are amazing to watch. What is also interesting about them is that they have a very long lifespan for a fish. 

They can live for ten plus years if well looked after. So if you want a fish that you will spend a lot of time with, you should consider a dwarf puffer. 

3. White Cloud Mountain Minnow

White Cloud Mountain Minnow 

The name white cloud mountain minnow is quite a mouthful, isn’t it? However, saying the name of this fish is the only thing that is challenging about it. This is because it is one of the easiest aquarium fish to keep. It can live in very cold water. Therefore, you will not need to buy or connect an aquarium heater to sustain it. It is also an omnivore so it can pretty much eat anything you can eat. 

This fish species is available in many color patterns but the silver version with white-tipped fins is the most common one.  It is a fish species that does not grow beyond 2 inches; so you can keep it in your nano aquarium for a long time. 

4. Micro Rasbora

Micro Rasbora

This is one of the best small fish to keep in a small fish tank. This is because it is a small fish that is peaceful and loves to swim. The fact that this fish is peaceful means you can keep it with other fish species. So if you want to have two or three different types of fish in your small tank, you should get this species first and pair it with another. 

This fish usually does not grow beyond 2 inches. So it is a species you can keep for long in your nano tank without needing to upgrade to a bigger tank. 

The one thing you should note about rasboras is that they love living in a group. So you should probably get two or three of them for your nano tank to keep them excited and sane.

5. Clown Killifish

Clown Killifish

The name of this fish may sound like it is dangerous but it is not. This is an African fish that is relatively peaceful and usually available in very exciting color patterns. The male clown killifish are usually quite brightly colored. They feature yellow and black stripes and have got fins also in striped color patterns. 

The female clown killifish often have less bright color patterns but are even more peaceful to keep compared to the male ones.

This fish species is perfect for adding color to a small aquarium and is great for small aquariums because it does not grow beyond 1.4 inches.

6. Least Killifish

Least Killifish

Least killifish aka mosqu aka midget livebearer is one of the smallest freshwater fish species kept in home aquariums. It is native to states like Florida, Georgia, Louisiana, and Alabama. The fish normally exists in olive color.

The best thing about this fish species is that it is small and does not grow much. This is what makes it perfect for nano aquariums. As a beginner, this is a fish species you will like keeping since you will also find it easy to feed as it is omnivorous and easy to maintain since it does not release a lot of toxic waste. 

7. Endler’s Livebearer

Endler’s Livebearer

Do you want a fish species that you know for sure likes living alone? Well, get an Endler’s Livebearer. This fish species is a member of the Poecilia family and it is a very attractive fish.

Before I tell you about its attractiveness let me tell you the most unique thing about it; as mentioned, it is a fish that likes living alone. Moreover, it shines on its own. So if you want a fish for your small tank that you will never feel sorry for keeping alone, you should strongly consider it.

Male livebearers exist in exciting and mesmerizing fluorescent color patterns, while female ones are usually grey or silver in color. The fish usually grow no more than 1.5 inches in length and can live for quite some time although not as long as bettas and dwarf puffers.

8. Crystal Red Shrimp

Crystal Red Shrimp

This is not a fish but it is one of the best alternatives to fish to keep in a nano aquarium. This is because of several reasons. First, it is a very beautiful shrimp. The female ones look amazing as they are very colorful. The male crystal red shrimps also look good but not as good as the female ones.

The best thing about keeping crystal red shrimps is that they really like moving. So if you want an aquarium life that will be constantly on the move, you should strongly consider getting yourself one. Crystal red shrimps like moving to look for food.

The maximum size a crystal red shrimp will get to is about 1.5 inches. 

To make your crystal red shrimp stand out in your small fish tank, make sure the gravel in it is dark. 

9. Guppy fish

Guppy fish

Guppy fish is a freshwater aquarium fish like most of the fish species on this list. It is a live-bearing fish that can thrive in many environmental conditions. Therefore, if you are a beginner aquarist, it is a fish you will like keeping because you will not need to know a lot or to be extremely careful and cautious about it.

Guppy fish species are available in many colors. The males are typically more colorful than the female ones. They usually have interesting color patterns and movements. 

Like a number of the aquarium fish on this least, guppy fish can feed on many things.

The one thing many people like about guppy fish is that they are perhaps the most affordable small aquarium fish on the market. Many sellers on places like usually sell them for very little. 

10. Neon tetra

Neon tetra

This is a fish species that is a characin family member. It is perhaps one of the most popular aquarium fish species in the Western World. It is easy to keep because it is well-adapted to multiple conditions. However, it best thrives in soft water that is cool or cold and slightly acidic. 

Neon tetras get to grow as big as 3.5 centimeters and no more. This is very convenient for you with your 5-gallon tank since it means you can keep it. 

According to expert aquarists, fish that can be used as tank-mates for neon tetras include barbs, smaller danionins, dwarf cichlids, and guppies. So you can have one neon tetra and perhaps one or two more fish of other species in your nano aquarium. 


As you can see from the information above, there are many types of exciting small fish that you can keep in a 5-gallon fish tank. They include neon tetras, guppy fish, dwarf puffers, bettas, and crystal red shrimps.

Before starting to keep any fish in your 5-gallon tank, you should read as much about it as possible to get all the details you need about keeping that fish. If you don’t read, you might end up with a dead fish pet within a couple of weeks, which is something you definitely do not want.

In my opinion, the best small fish to keep in a 5-gallon fish tank or a nano aquarium is a betta fish. This is because betta fish are perhaps the most attractive small aquarium fish on the planet. They are very colorful, active, playful, fun, and intelligent. They can actually grow and learn to recognize you.

The only problem with them is that they are not the most affordable aquarium fish on the market. But if the money is not an issue, you should strongly consider getting a Betta. The other options on my list are also very nice for nano aquariums.