Tank And Equipment

Best Tank Size For Tetra Fish? Neon, Cardinal and Other Similar Tetras

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Tetra fish are a group of small fish originating from the parts of water bodies from Central America, South America, and Africa. The size of the Tetra fish usually ranges from 2 inches to 5 inches at the most. These tetra fish typically require very little attention and care. These small Tetra fish keep on darting all around your tank and will fill up the entire water column. Keeping these tetras gives your tank a fuller look. You will find out more about what is the best tank size for your tetra fish.

Tetras don’t eat live plants so that it will be the right choice for you in your planted tanks also. Tetras are some of the most common group of fish which you can find in almost every local fish store. Tetra fish are one of the most kept fish in our hobby.

Many tetra fish myths circulated as the number of tetra fish kept as a hobby increased. Most people think that they can house tetra fish in a small tank, which can only contain very little water. Tetra fish are small, but you should not keep them in any container more modest than a 10-gallon aquarium. Like any other fish, the Tetra fish produce biological waste, and if the tank is small, it will lead up to toxic build ups causing the death of fish.

Basic Aquarium Requirements for Tetra Fish

The aquarium tank housing the tetra fish should be at least 10 gallons. It should be fitted with a water filtration system, a water heater, substrate, and cycled water containing a lot of beneficial bacterias. A sound water filtration system keeps the water clean and maintains circulation in the tank.  You may find the need for a great heater to keep the temperature in check of the aquarium. A cycled water so your fish won’t die as soon as you add them to your tank. 

We have other articles regarding the tetra tank set up as well.

However, there’s one thing that most of us ignore; it is the size of the aquarium housing the fish. Choosing the right size of the aquarium can get tricky at times, considering if you are new to this hobby. Here’s some guidance for you on getting the perfect size of tank for your tetra fish.

Best Sized Tank for Tetra

There is not any precise size of the tank for your tetra fish. The size of the container depends on various factors. It depends on how many fish you place on your aquarium. It depends on how often you do water changes, and the size of the tank also depends on how proper the filtration is in your tank. These are some of the most critical factors that will help you with choosing the right size of tank for your tetra fish.

If you are willing to do regular water changes in a short interval, a smaller proportion of the tank would not be that bad. However, if you’re not ready to go through the hassle of doing water changes over and over again, and if your filtration is also not top-notch, you will be better off with a larger tank.

But there is a minimum requirement regarding the size of the tank for tetra fish. The tank should hold at least 10 gallons of water. You should keep your tetra fish in a group of 5 or more, and a 10 gallon should hold 5-8 tetras. The amount of water is very crucial in your tank. Having a very less amount of water causes many problems. The water will get polluted quickly, and the ammonia and nitrates level will also spike up very quickly.

Thus it is always better for you to opt with a bigger tank in every scenario.

Why Do you Need a Right Sized Aquarium?

The goal of fish keeping is not just to be able to make the fish survive in your tank. You should be able to provide the fish with a suitable environment in which the fish can thrive and grow to its full potential. If you are willing to set a tank for a small group of tetras, I would recommend you set up a 10-gallon long aquarium, and with increasing numbers of fish, you should increase the size of the tank too. Your best bet would be to get a larger tank than what you require. A large tank enables you to add fish anytime you want. You will not have to overstock your tank and will be able to get new fish without having to set up a new tank. You should get at least a 10-gallon tank, and anything more significant than that would be preferred.

I would suggest you get a more extended tank rather than a tank, which is taller as the tetra prefer to swim fast in a straight line. The length of your container should be larger than the height and breadth of the tank. And a longer tank will be much more suitable for this rather than a taller tank.

Why You Should Avoid a Smaller Tank

With a smaller sized aquarium, the margin of error is very thin. Things can go from bad to worse in a matter of seconds. The temperature of the tank gets changed pretty quickly, and it is harder for you to maintain a constant water parameter. You will have a hard time getting the parameters correct in a small tank, and even if you do, it is challenging to maintain those parameters precisely. In small tanks, the rate of biological filtration is also very low and almost negligible while comparing it with the biological filtration in a larger tank. The small number of beneficial bacteria cannot convert the harmful toxins most of the time, which causes an outbreak of various diseases in your fish.

Disadvantages of a Smaller Tank

The disadvantages of a smaller tank heavily outweigh the advantages. There is a very limited swimming space for your fish to swim. There is no enough room for the fish to swim properly and explore. The small size of the tank also limits the hiding spaces which the tetra fish require to hide while they are stressed out. Smaller tanks tend to get dirtier quickly. You will be cleaning the smaller tank much more often than a larger tank. It is extremely hard to maintain constant parameters, and even a little bit of change in the number can cause major problems in the entire tank. The tank water temperature also can increase or decrease very quickly. All these changes in the parameter of water in your tank will cause the fish to stress out and may eventually kill the fish.

Why Do you Need a Bigger Tank?

Bigger is always better. You should stick to this saying when it comes to choosing the aquarium tank for your fish. A bigger tank is always better. It is much easier to maintain. You can keep the parameters in check and constant very easily. Chances of anything going wrong over a short period are very low. You can observe anything and easily diagnose it in a larger tank rather than in a smaller tank. A larger tank gives much more space for the fish to swim in. Your fish will have a lot of space to grow into. Your fish won’t be stuck in one corner like in a smaller tank.

Overall you and your fish will be a lot happier with a bigger tank. The chances for you to encounter any breeding habit in a large tank are exponentially higher than the chances of the same fish breeding in a smaller tank.

Advantages and Disadvantages of a Larger Tank

Everything has its own advantages and disadvantages. The size of your aquarium will also have its downsides to it. If you had to choose one, you would be better off choosing the option that has higher advantages than disadvantages. Larger tanks are a lot easy to work on than on smaller tanks. You can easily clean the tank, do water changes, and maintain the correct parameters in the tank. You will always have a higher margin of error in a larger tank. A larger tank is a lot more forgiving too.

There are relatively fewer disadvantages to the large tank. Not everything that has to do with a larger aquarium is good. They cost quite a bit, and that might be a problem for many people. A larger tank requires a larger filter, which also adds up to your cost. Your total running cost will also increase with the increase in the size of the tank. You should be well prepared for a large electricity bill and water bill if you have multiple numbers of large aquarium tanks.

Decorations in The Tank

The tetra fish require very minimal decorations for their survival. However, you can add plenty of decorations, plants, stones, caves, etc. for the fish to interact and stay busy. The tetra fish can use the caves and stones for swimming through and also hiding when they feel threatened or stressed. Adding various decorations will also make your aquarium look more attractive.

You can also reflect your creativity in your aquarium tank, and your tetra fish will love you for it.


Even before you buy your first school of tetra fish, you should be well prepared with a well-conditioned and cycled tank of an appropriate size. The size of the tank is an important aspect that you should consider. The health of your fish primarily depends on the size of your tank.

The lifespan of the fish also depends indirectly on the size of the fish tank. Fish in smaller tanks usually have a shorter life span than a fish is a larger tank due to limited space for proper movement. There is no such downside for choosing a larger tank in fish keeping; it is always better getting a larger tank than what your fish requires.

Image Reference: https://www.flickr.com/photos/sophistechate/2953767257

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