How Many Neon Tetras Per Gallon Of Water | Different Gallon Tanks?

How Many Neon Tetra in different Gallon Tank

Tetra fish are some of the most highly in demand aquarium fish out there. Many fish enthusiasts prefer these fish because tetras are very easy to take care of, colorful, and highly adjustable to certain changes in the aquarium environment. Especially the neon tetras, they are the most purchased tetra fish. Neon tetras are beautiful, bright tetras having red, blue, and translucent colors. You will know many neon tetras that you can keep on different gallon tanks depending on the size of your aquarium in this article.

The neon tetras originate from the South American freshwaters. These tetras are very popular and highly regarded. Because of the tetra’s nature these fish are favored and appropriate for your home aquarium. Some of the common traits of the neon tetras are they are compatible, energetic, peaceful, and ideal for varying water parameters. 

However, many of you must be wondering how many neon tetras to keep in your tank? Since the tetras are schooling fish, you cannot just put one. Moreover, is there something as too many tetra fish? Do not worry; by the end of this article, all your doubts will be clear.

General Rule for Housing Neon Tetras

You will know that these are shoaling fish if you know the tetra species. In other words, the tetras tend to be in at least five groups. Therefore, you cannot push the neon tetras into a small compact area. Well, what is the appropriate number of fish you can keep?

Initially, determine how big neon tetras can get. The size of the fish enables you to evaluate how many tetras you can sustain in various tank sizes. Neon tetras are usually up to 1.5 inches to 2 inches long. What you have to do is measure the numbers by calculating.

The general rule of thumb is that 1 gallon of water is required by 1 inch of fish. Neon tetras can grow up to 2 inches. Thus, one neon tetra requires tentatively 2 gallons of aquarium water. Considering your tank has some decorations, which takes up some space. So, let us say 3 gallons of water are covered. Hence, you will be able to keep around four neon tetras in the case of a 10-gallon tank (10/3=3.33 or 4). You can increase the number to five or six depending on the quality of your tank environment. 

You should check out our detailed article on how many neon tetras can you keep in a 10-gallon tank for further information. 

Neon Tetras in 3 Gallon Tanks

When you are a fish enthusiast but do not have space for big aquariums, you opt for the smaller ones. Even though smaller fish tanks are great home decorative, you cannot keep much fish in them. In the case of 3-gallon tanks, you should provide special care and choose the right fish to go with it.

You could keep only 1 neon tetra in a 3-gallon tank. However, keep in mind that you will not have enough room in the tank to play around and add more items. Therefore, it is also not advisable to hold neon tetras in less than 10 gallons.

Neon Tetras in 5 Gallon Tank

Just as with the 3-gallon tank, the 5-gallon tank will also limit the amount of fish you could keep. 5-gallon tank (Buy Online) is quite small, but it can be a good starting pack if you are a beginner. At most, you can house around 2 or 3 neon tetras in the 5-gallon tank

When you get the gist of handling the neon tetras, you can move into bigger tanks. It may be necessary to move the neon tetras into the larger than when they breed. Also, you will find difficulty in maintaining the smaller tanks as compared to the larger tanks. I recommend that it be better to get at least a 10-gallon tank than to degrade the water quality.

Neon Tetras in 15 Gallon Tanks

By the rule of thumb, for a 15-gallon tank, you can keep 15/2 inches =7.5 or 8 neon tetras. Moreover, you should be easily fit 10 to 12 neon tetras if you take care of them and maintain the water quality. That being said, you should also add other aquarium equipment such as filters, air pumps, heaters, plants, etc. if you want to keep more neon tetras. 

Before you stock up your aquarium with a number of neon tetras, you must conduct thorough research. This is because you will not just be keeping neon tetras. You will need to research what other species you can keep along with the neon tetras. You can keep guppies, angelfish, or mollies with the tetras. Mostly, the tetras should not feel cramped. 

Neon Tetras in 20 Gallon Tanks

If you choose to get a 20-gallon tank (Buy Online), you will get a lot of opportunities to explore criteria that are suitable for your fish. According to the rule of thumb, you will be able to keep 10 to 13 neon tetras in a large 20-gallon tank. For a community tank of twenty gallons, you can also get a mix of fish species and hold neon tetras.

In the majority of fish stores and the online market as well, 20-gallon tanks are available. The best neon tetra tank size is a 20-gallon tank, as you will have plenty of room to add more decorations, rocks, and accessories. To Neon Tetras, this makes it ideal because they prefer tanks with plenty of space to hide.

Neon Tetras in 29 Gallon Tanks

A 29-gallon tank is a pretty decent tank for any kind of fish species. You will be able to keep bit extra neon tetras in the 29-gallon tank along with few other tank mates. The number of neon tetras you can keep in the 29-gallon tank is 15 to 18. 

You may also add a few ghost shrimps, bettas, guppies in this tank. If you have a good filter, managing a 29-gallon tank will be very easy. Remember to add live plants as well in the tank with plenty of rooms for the fish to swim freely.

Neon Tetras in 30 Gallon tank

A perfect community tank for various species can be a 30-gallon tank. The 30-gallon aquarium is even larger than a 10 or a 20-gallon aquarium. Now, that is quite perfect for Neon Tetras because they are constantly swimming around the tank. There is also less chance of tetras hiding. 

A big school of 15 to 20 Neon Tetras can be kept in a 30-gallon tank. You will start seeing their actual schooling activity and become more involved with this amount of Neon Tetras. These tetras are active swimmers and must swim all across the tank. 

The tank size is suitable for medium fish such as Angelfish, Rams, Barbs, and Dwarf Cichlids.

Neon Tetras in 50 Gallon Tanks

A very flexible tank that offers an ample amount of space for many varieties of fish as well as plants. Choosing a 50-gallon tank is an adaptable choice. You can allow yourself to experiment with your aquarium and make it more appealing. As attractive a 50-gallon tank sounds, it can be quiet expensive as well. The scale of this size of the tank is 36L X 18W X 19H. 

That being said, you will be able to house around 25 to 30 of the neon tetras. You might also want to add some cardinal tetras, betta, angelfish, shrimps, and many more. It is also a good idea for you to add many plants and decorative to achieve natural looks and feel. 

Just do not forget the regular water maintenance, such as partial water changes and filtration. For the tank of large scale as 50-gallon, you might need a strong filter. I recommend you get a filter that performs all three filtrations: Biological, Chemical, and Mechanical.

Neon Tetras in 55 Gallon Tanks

Your desire to purchase an aquarium that covers a large area, then this is the right one. Similar to the 50-gallon tank, the 55-gallon also holds numerous species. A tank of 55 Gallons is sufficiently wide to house 28 to 36 Tetras. These tanks are widely popular and surprisingly comes under a suitable budget as well.

A 50-gallon tank is relatively larger than other comparative fish tanks and provides enough horizontal swimming space. These are also a little taller than most fish aquariums and ideal for Neon Tetras since they prefer swimming in the middle of the fish tank and on the top deck. 

Difference between the 29 Gallon Tank and 30 Gallon Tank

If you have confusion about the sizes of 29 gallons and 30 gallons, you do not have to be. This is because; there is not much of the difference. You can choose either 29 gallons or 30 gallons of the tank sizes, or you will do fine.

The major noticing difference is the scales of the aquarium. A 29-gallon tank would be of scale 30L X 12W X 18H. On the other hand, the 30-gallon tank would be of the scale 36L X 13W X16H. Even though the height of the 30-gallon aquarium would be slightly less than that of 29 gallons, it does not affect your fish in anyways.

Moreover, if you choose to purchase and install a 30-gallon tank, you will be able to house a longer fish. This can be a great addition to your tank’s attractiveness.

Why Are Smaller Sized Fish Tanks Not Preferred?

Although this article states about the number of neon tetras you can keep in 3-gallon and 5-gallon tanks, it is not an ideal situation. Almost all fish experts will recommend you to get a bigger aquarium. Especially if you are a beginner, you may think that a smaller aquarium tank will be easy. However, this is not the case.

In smaller tanks, you will have difficulty in stabilizing the tank environment as per the fish you have. Hence, you will not have any rooms to make mistakes. To add, you will definitely not be able to correct your mistakes in a smaller tank. 

A young fish that grows in a too-small tank can suffer from slow growth, spinal deformities, atrophied muscles, and other developmental healing problems. This will adversely affect the health of the fish causing fish life to shorten. 

Thus, aquarium tanks that are of at least a 10-gallon or 20-gallon tank are recommended to the beginner fish keepers.

Can You Add More Number Of Fish Into A Tank Than General Rule Of Thumb Sates?

That depends. Let us take an example of a 40-gallon tank. In a 40-gallon tank, you can add 40/2 inches = 20 fish, in the case of neon tetras. It is not a strict rule that you have to add exactly 20 neon tetras. You can add 22 or 25 neon tetras. The only thing that you have to take care of is the quality of the tank environment. By adding more fish, you will have to clean the tank on a regular basis, and good regular monitoring is required. Overall, you will have to look after your fish. 

Factors You Must Consider In a Neon Tetra Tank

Certain tank conditions are necessary to house neon tetras. Some of them are enlisted below:

  1. Neon tetras need temperatures between 70 degrees F to 81 degrees F. You may use aquarium heaters available on the market to control this temperature.
  2. Keep the pH level around 6.5 and the hardness level at 10 dGH.
  3. Neon tetras need a matured tank, cycled for at least 4 months. 
  4. A good nitrogen cycle in the tank must be established.
  5. Install large substrate to avoid neon tetras eating them.
  6. Plant many live plants as well as semi-aquatic live plants.
  7. Feed 2 or 3 times a day and avoid overfeeding.


Before making any decision about the tank sizes, make sure that you conduct good research. Focus on how much time and dedication you are willing to give to your fish. Do not go overboard with the fish if it is your first time. Once you build up the confidence, then gradually increase the amount of fish or the size of the tank.

I hope that you have all the necessary ideas about the amount of fish you can keep in the various gallons of tanks. Choosing the right size of the tank is very important, and following the above guidelines will definitely help you. 

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