Neon Tetras: Care, Tank, Food, Breeding & Health

About Neon Tetras

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Neon Tetras are a type of freshwater fish native to the Amazon Basin: an area of South America that spans more than 2.5 million square miles. Most of the Amazon Basin is covered by the Amazon rainforest, which is the largest rainforest in the world. 

In the Amazon, Neon Tetras are commonly (though not exclusively) found in “blackwater”. Blackwater is a term used to describe bodies of water that move slowly through areas of dense vegetation, such as swamps or marshes. When plants die, they rot in the water and release tannins which turn the water a dark color. The rotting process also makes the water acidic.

Neon Tetras were introduced to the aquarium hobby in the 1930s, though they didn’t become widespread until after the Second World War. 

Today, Neon Tetras are one of the most popular freshwater fish species in the world due to their small size, beautiful appearance, vibrant colors, and fascinating schooling behavior. 

Where to buy Neon Tetra fish

As Neon Tetras are one of the most popular aquarium fish in the world, they can be found in the vast majority of pet stores. 

There are also a large number of online retailers that sell Neon Tetras. Some online retailers may allow you to choose specific individuals based on photographs and videos of the fish.

When you order online, a reputable fish store will pack the fish in special packaging to keep them safe during their journey to your home.

How much does a Neon Tetra cost?

Neon Tetras are not expensive. In fact, each fish should cost you just $2 or $3 USD or the equivalent in your currency. 

However, you don’t buy Neon Tetras individually. Neon Tetras should be kept in groups with others of their kind. You’re therefore likely to buy 6 or more Neon Tetras at a time, so should expect to spend around $15 or more on your first batch of fish.

In addition to this small cost for the fish, you’ll also have to budget for a suitable tank, equipment, and consumable supplies such as food and water treatments. 

It’s easily possible to spend over $100 setting up a Neon Tetra tank complete with your fish, a filter, an air pump, plants and decorations.

How long can Neon Tetra fish survive in the bag?

How long Neon Tetra fish can survive in a bag will depend on the size of the bag, how much water and oxygen is in the bag, and how many fish are being kept inside.

Obviously, a bigger bag with lots of water and air available – and fewer fish sharing the same bag – will allow the Neon Tetras to survive longer than if lots of fish are all together in one small bag. 

Generally speaking, we would not want to keep Neon Tetras in a bag for more than one day. This is why most online fish retailers will deliver live fish with next day delivery.

You should make sure that your tank is all set up and ready for your fish before buying them from the store or having them delivered. This will keep the time they need to spend in a bag to a minimum.

Where do Neon Tetras come from?

Neon Tetras originally come from the Amazon Basin, where they are found in the slow-moving rivers and streams of the Amazon rainforest.

However, it’s unlikely that the fish you buy at the pet store – or any of their recent ancestors – will have been to the Amazon. Neon Tetras were first introduced to the aquarium hobby almost a century ago, so the fish we buy today come from long lines of captive-bred specimens. 

What to feed Neon Tetras

What do Neon Tetras eat? Pretty much anything that will fit into their tiny mouths! 

Neon Tetras are omnivores, which means they will eat both plant and animal matter. This means that you can feed your Neon Tetras flakes, pellets, vegetables, or freeze-dried live foods such as bloodworm or brine shrimp.

Rather than just feeding flakes all the time, or picking only one type of food for your Neon Tetras, it’s best to feed them a varied diet. Just like humans and other animals, your Neon Tetras will benefit from a varied diet containing all the vitamins, minerals and nutrients they need to stay healthy.

The only thing that you should bear in mind when choosing food for your Neon Tetras is that their mouths are very small! You will need to crush food into small pieces to allow them to eat it properly and avoid large chunks going to waste and rotting at the bottom of your tank. 

How much to feed a Neon Tetra

We recommend feeding Neon Tetras twice per day. 

Each time you feed Neon Tetras, you should put a small amount of food into the tank and watch as they eat it. Give them two minutes of eating time and then remove any uneaten food from the tank with a net. 

Feeding as much food as Neon Tetras can eat in two minutes, twice per day, will be plenty to ensure your Neon Tetras are well fed, but without the risk of overfeeding.

How long can neon tetras go without food?

Neon Tetras can survive for several days without food. 

In a normal tank set up, if you were to leave Neon Tetras unattended for one week, they would be unlikely to starve while you were away.

In a tank with lots of live plants, Neon Tetras could survive for weeks without being fed.

Neon Tetras can go for several days without being fed because their bodies are adapted to survive long periods without eating, but also because there is always more food than you think in your tank.

Every time you add food to your tank, some of it will inevitably go uneaten and will not be picked up when you clean your tank. And if you have live plants in your tank then small pieces will break off the plants all the time. These tiny pieces of uneaten food and plant matter can be plenty to sustain a Neon Tetra for days or even weeks. 

How many Neon Tetras in a school?

Neon Tetras should be kept in large groups, rather than individually or in pairs or threes. So, how many Neon Tetras are needed in a school (or a shoal)?

Our minimum recommended number of Neon Tetras to keep together is 6. 

However, it is a case of the more the better. So, if you have enough room in your tank for 8 Neon Tetras, 15, 20, or more, we recommend keeping as many as you safely can. 

How to make Neon Tetras school

Neon Tetras are a shoaling fish, which means that they will group together when stressed or when they feel threatened. This is a little different to schooling, where fish stay together in a tight group all of the time and swim in a synchronised formation. 

To make Neon Tetras display schooling behavior you should keep a large number of them together (at least 6, preferably more) and ensure they have plenty of space to swim around. 

Even then, you may find that you only see the schooling behavior you’re looking for when your Neon Tetras are startled or stressed. Hopefully this won’t be very often and – as it is cruel and will cause them to get stressed – you should never deliberately startle your fish just to see their schooling behavior. 

How long do Neon Tetras live?

With proper care, Neon Tetras will usually live to be 5 years old. 

Some individuals will live even longer, with 5 to 10 years being a typical lifespan for a healthy and well cared for Neon Tetra. 

Factors that affect the lifespan of a Neon Tetra include water quality and temperature, tank size, diet, tank mates, and genetics. 

As a fish-keeper, you can influence all of these factors except for genetics. The quality of care that you give to your Neon Tetras will therefore have a big impact on how long they live.

How big do Neon Tetras get?

Neon Tetras are small fish. The size of a Neon Tetra fish can vary depending on the individual, but they rarely grow to be more than 1.5 inches long. That’s less than 4cm.

Male Neon Tetras are generally slightly longer than females.

How long until Neon Tetras are fully grown

It will take around 6 to 9 months for Neon Tetras to reach their fully grown adult size. 

The Neon Tetras you see in the store may already be around 3 months old, so it may only take your Neon Tetras around 3 to 6 months from the day you bring them home to reach their full adult size.

How to tell the age of a Neon Tetra

When you first buy Neon Tetras from a pet store, they are likely to be around 12 weeks old. At this age, Neon Tetras are already able to breed.

Up to the age of 9 months old, you can attempt to estimate the age of a Neon Tetra by looking at their size.

If the Neon Tetra is 1/4 inch long (6mm) or less then it is under two months old. 

Between 2 months and 9 months old, the Neon Tetra will slowly grow from 1/4 inch to between 1 and 1.5 inches long. Looking at the length of your Neon Tetra will therefore allow you to have a guess at its age.

By 9 months old, most Neon Tetras will have reached their full adult size. Beyond this point, it is essentially impossible to look at a Neon Tetra and work out how old it is. 

Where possible, the best way to know the age of your Neon Tetra is to note its date of birth, or make a note of the date you bought it, then add approximately 12 weeks.

Neon Tetra Tank Size

When deciding how big a tank to buy for your Neon Tetras, you should first think about how many gallons one Neon Tetra needs, then work out how many gallons you’ll need for a group of Neon Tetras.

As a general rule, you should allow 2 gallons of water per Neon Tetra. 

So, to work out how big a tank you need, simply multiply the number of Neon Tetras by two. 

For example, we recommend keeping Neon Tetras in groups of 6 or more. 6 x 2 = 12, so a group of 6 Neon Tetras would ideally live in a tank of 12 gallons or more. 

Alternatively, you can work the other way round: Start with the size of your tank and divide by two to see how many Neon Tetras could comfortably live in a tank of that size. 

This method will give you a rough estimate. You may be able to keep afewmore fish than this calculation suggests, but not many more. 

How many Neon Tetras in a 40 gallon tank?

If you have a 40 gallon tank and each Neon Tetra needs 2 gallons of water then you have enough space for 20 Neon Tetras. 

As a 40 gallon tank is quite large, you may be able to relax the 2 gallon per fish rule a bit, and perhaps push towards 25 Neon Tetras, but we wouldn’t go for any more than that.

How many Neon Tetras in a 30 gallon tank?

A 30 gallon tank is enough for 15 Neon Tetras to have 2 gallons of water each. 

We would keep between 15 and 18 Neon Tetras in a tank of this size.

How many Neon Tetras in a 20 gallon tank?

At 2 gallons per fish, a 20 gallon tank is large enough for 10 Neon Tetras.

At a push, you could perhaps keep 12 Neon Tetras in a 20 gallon tank.

How many Neon Tetras in a 10 gallon tank?

If you relax the 2 gallons per fish rules slightly then you could keep a group of 6 Neon Tetras in a 10 gallon tank. We certainly wouldn’t keep a group any larger than this in a tank of this size.

If possible, it would be worth considering buying a larger tank. 

How many Neon Tetras in a 5 gallon tank?

A 5 gallon tank is too small for Neon Tetras. These fish should be kept in groups of 6 or more individuals, and 5 gallons just isn’t enough for that many fish, even if they are small.

Neon Tetra Tank Size Chart

The table below shows how many Neon Tetras we would recommend – and the maximum we would ever include – in tanks of various sizes.

Tank SizeRecommended number of Neon TetrasMaximum number of Neon Tetras
60 gallons3040
50 gallons2533
40 gallons2025
30 gallons1518
20 gallons1012
10 gallons56

What decorations are best for a Neon Tetra tank?

Neon Tetras enjoy living in quite heavily planted tanks with lots of foliage and roots of floating plants to hide behind and explore. However, they also enjoy swimming around in open space. 

It’s therefore a good idea to make your Neon Tetra tank quite varied, with some heavily planted areas – perhaps also containing decorations, rocks and caves to explore – plus some areas of open water. 

By decorating your tank with lots of plants but also maintaining some open space, you will keep the environment interesting for your Neon Tetras and for yourself. In this kind of setup you’ll be able to enjoy the sight of your fish swimming as a group out in the open, while also observing interesting behaviors as they explore plants, caves and other decorations too.

How much salt can Neon Tetras tolerate?

Neon Tetras are freshwater fish, not saltwater fish. This means that they are not adapted to survive in salt water and salt can be extremely bad for their health. Even a short amount of time in salty water can be lethal for a Neon Tetra.

Neon Tetras may be able to tolerate a very small amount of salt – say, a single tablespoon of aquarium salt per 5 gallons of tank water – but our recommendation is to avoid salt entirely.

Freshwater fish should not be kept in the same tank as saltwater fish, as they are not compatible, so there shouldn’t be any reason to add salt to your Neon Tetra tank.

And while it is true that salt is sometimes used for medicinal purposes, it is so dangerous to Neon Tetras that we would avoid it entirely and choose another treatment wherever possible. Otherwise, it may do more harm than good.

What temperature should Neon Tetras be kept in?

Neon Tetras should be kept in water with a temperature of between 72°F and 78°F. That’s about 22°C to 26°C.

It is a good idea to use an aquarium heater to heat your tank water to within this range and then keep the water temperature stable. Sudden changes in temperature can cause stress to fish, which is not good for their health.

What is the lowest temperature Neon Tetras can tolerate?

Our minimum recommended temperature for Neon Tetras is 72°F / 22°C. However they can tolerate lower temperatures.

The lowest temperature that a Neon Tetra could tolerate for any extended length of time would be around 68°F / 20°C. Much lower and the fish would go into shock and be unlikely to survive for long.

What pH do Neon Tetras prefer?

Neon Tetras can tolerate quite a wide range of pH levels. However, they prefer neutral or slightly acidic water. Aim for a pH of between 5 and 7 if possible.

The natural environment for a Neon Tetra is “blackwater”. This is water that has been stained a dark color by tanning leaching from rotting plant matter. This rotting process also makes the water slightly acidic, so Neon Tetras are well adapted to living in slightly acidic water with a pH of less than 7.0.

How do Neon Tetras breed?

Neon Tetras will breed when males and females of breeding age (anything older than just 12 weeks!) are in a tank with the right conditions. 

The ideal breeding conditions for Neon Tetras are low light levels, an acidic pH of between 5 and 6, and a relatively low temperature of around 75°F / 24°C. The tank should contain plenty of plants for the eggs to stick to. This also gives newborn Neon Tetras a place to hide.

The male will start the breeding process by swimming around the female in short bursts. The female will then lay her eggs for the male to fertilize.

How to tell if a Neon Tetra is male or female

The easiest way to tell whether a Neon Tetra is male or female is to look at the size of their belly. 

Female Neon Tetras have a fatter belly, which makes the stripe along their body seem to curve. Males have more slender bodies and a straight stripe. 

Male Neon Tetras are also usually slightly longer than females.

How to tell if a Neon Tetra is pregnant?

If you’re new to Neon Tetras and are interested in breeding them, then you may be wondering what a pregnant Neon Tetra looks like. However, the first thing to understand is that Neon Tetras don’t get “pregnant”. This is because Neon Tetras lay eggs, rather than giving birth to live young. 

That said, if you were thinking that your Neon Tetras fat belly might be a sign that you’ll soon have Neon Tetra babies, then you may well be right!

A fat belly is a sign that your female Neon Tetra is carrying lots of eggs, which she may soon lay to be fertilized by a male.

What to do if your Neon Tetra is pregnant

As explained above, Neon Tetras don’t get pregnant because they lay eggs rather than giving birth to babies.

If your female Neon Tetras are carrying lots of eggs then try putting them in a tank with some males and a spawning mop. Then, decrease the temperature of the tank water and lower the light levels. This should be enough to induce spawning.

What do Neon Tetra eggs look like?

Neon Tetra eggs are like very small round balls of jelly. They have a yellowy-white color and you’ll find them stuck to plants.

How long does it take for Neon Tetra eggs to hatch?

It doesn’t take very long at all for Neon Tetra eggs to hatch. Usually the babies will hatch out of the eggs within 24 hours of the egg being laid. 

Once your Neon Tetra eggs have hatched, you will need to separate the babies from the adults so that the adult fish can’t eat them!

How many babies do Neon Tetras have?

Neon Tetras can often lay more than one hundred eggs in a single spawning. However, not every egg will be fertilized or hatch. 

From 100 Neon Tetra eggs, you may end up with perhaps 20 to 50 baby Neon Tetras.

Neon Tetra Health

Neon Tetras don’t have a reputation for being a particularly hardy fish. In fact, we’re often asked why Neon Tetras die so easily. 

The answer is that people often keep Neon Tetras in groups that are too small (less than 6) and in unsuitable tank conditions.

Given the right tank mates and stable and correct water conditions and temperature, there’s no reason why Neon Tetras shouldn’t live for five years or more.

What is Neon Tetra Disease?

Neon Tetra Disease is a serious health problem that is caused by a parasite. It affects many different types of fish, not just Neon Tetras. 

What does Neon Tetra Disease look like?

The first symptom of Neon Tetra disease is usually erratic swimming. Instead of swimming calmly with the other Neon Tetras, the sick fish will split off on their own and dart around in a restless, erratic pattern.

As Neon Tetra Disease progresses, the fish will lose color, develop cysts on its body, and its body may become noticeably curved.

How long does Neon Tetra Disease take to kill?

There is no fixed amount of time that it will take for Neon Tetra Disease to kill. Often, Neon Tetras will live with Neon Tetra Disease for several months. 

Unfortunately, Neon Tetra Disease gets worse over time. So while symptoms may initially be mild, and the fish may survive for months, they will get sicker and sicker as time goes on.

Why is my Neon Tetra swimming at the top of the tank?

If your Neon Tetra is swimming at the top of the tank then this is usually a sign of low oxygen levels in the water. 

Oxygen dissolves into water through movement at the water’s surface. This means that the highest oxygen levels can be found near the top of the tank.

If oxygen levels are too low elsewhere in the tank, fish will swim to the top, where more oxygen is available.

Cooler water holds more oxygen than warm water, so if you suspect your tank has oxygen levels that are too low, you may want to consider lowering the water temperature. 

You can also introduce more oxygen by causing more movement and ripples at the water’s surface. This can be done by adjusting the flow of your filter or by adding an air pump.

Why is my Neon Tetra swimming at the bottom of the tank?

Swimming at the bottom of the tank isn’t always a problem. However, if your Neon Tetras are always near the bottom of the tank – perhaps sitting still or behaving strangely – then it is likely to be a sign of stress or disease.

Before assuming that your fish are sick, you should first check your water temperature and water parameters. 

Is the tank water between 72°F and 78°F (22°C to 26°C) as it should be? Are ammonia and nitrite levels at zero as they should be? Is the pH level below 8, or ideally lower? Are your Neon Tetras in a large enough group (6 or more) and do they have plenty of plants to hide behind and explore?

If any of these parameters are far away from where they should be then try making the appropriate change to your Neon Tetra tank and see if their behavior improves.