Why Are My Neon Tetras Dying?

Neon Tetras are wildly popular due to their beautiful appearance, with silver bodies and blue and red stripes running all along them. In the wild, neon tetras inhabit very soft acidic water, and they can have a lifespan of as long as ten years! 

If they live so long, you may be asking “why are my neon tetras dying?” Although Neon Tetras have a reputation for being easy to care for, some of them have lost their natural hardiness due to overbreeding, and their lifespan in an aquarium is between two and three years under ideal conditions. Let’s explore why your neon tetras might be dying, further.

Why Are My Neon Tetras Dying

Neon Tetras are excellent pet fish and popular for first-time fish owners. However, they can die very quickly when environmental change occurs. 

If there are any dramatic changes in the chemistry of the water, they could start experiencing stress and depression, which results in low immunity. 

Let’s look at the most commonly known reasons for Neon Tetras dying.

Your Neon Tetras Will Die If They Are Not Kept In Schools

Why are my neon teras dying? They need more friends. Neon tetras are social fish and should always be kept in schools to thrive to their fullest potential. 

When neon tetras are unable to find a lot of their friends around, they will become scared, insecure, and go into a constant state of stress. 

This stress and insecurity could result in aggressive and territorial behaviors such as biting on other tetra’s fins. 

This is the most common and significant demise of neon tetras. Many fishkeepers decide on only keeping two or three neon tetras at first, but it doesn’t work well. A school of six neon tetras is seen as the bare minimum. 

Tetras prefer to stay in large groups due to their small size, as they easily fall prey to other big fish. Also, staying in a school makes it easier for them to travel as well, so it’s just a natural instinct!

Your Neon Tetras Will Die If You Overfeed Them

Overfeeding is the biggest problem in smaller-sized aquariums. The more food you provide your neon tetras, the more waste they will produce in their tank, influencing the ammonia levels. 

Uneaten fish food and fish waste will make the water unsuitable for your neon tetras. Your bacteria colony can help to balance the water chemistry. 

Still, the toxic environment could cause your neon tetras’ death, as they are sensitive to ammonia changes in their water.

Your Neon Tetras Will Die If Their Water Is Unsuitable

The quality of your aquarium water will impact the overall health of your neon tetras, which will also largely determine how long they live. 

Poor water quality could affect any creature you may have in your aquarium, making them more susceptible to disease and encouraging them to perish before their time. 

When your neon tetras keep dying, you need to consider the following water-related issues.

There Is No Stability In Your Aquarium

Neon tetras require stability to flourish. They will not respond positively to aquariums whose water chemistry is constantly changing. 

Of course, you will need regular water changes to keep your aquarium clean, but it could alter the chemistry of your tank, which could significantly harm and lower your neon tetras’ immune system. Rather than carrying out complete water changes, swap out the water slowly, adding new water a little at a time every few days rather than all at once.

Your Aquarium May Have Incorrect Water Parameters

You need to keep your neon tetras in parameters that are ideal for them. Pay very close attention to your aquariums’ temperature, nitrate levels, hardness, and pH. 

Along with causing your neon tetras to go into stress, the wrong water parameters will make your fish sick and kill them if you do not treat your aquarium effectively.

why are my neon tetras dying

Your Aquarium Might Have Poor Hygiene

If you cannot keep your aquarium clean, you will expose your neon tetras to high concentrations of toxins, including ammonia. 

Ammonia could be the death of your neon tetras and as well as other toxins that build up, including chlorine. You can avoid these risks by cleaning your tank regularly and safely. 

Your Aquarium Wasn’t Cycled Correctly

Aquariums that have not been allowed to cycle to completion are prone to spikes in nitrates and ammonia that will kill your neon tetras. 

New tanks continue to be dangerous, even if properly cycled, as bacteria colonies that generally process the contaminants are not adequately established yet. 

Because of this, nitrates and ammonia may continue to spike even though you have cycled your aquarium to completion. 

This is why experts advise fish-keeping beginners to only introduce neon tetras to their new tanks at the three to six-month mark. 

However, this is not a fixed rule that needs to be followed, but older tanks tend to be more stable, which means they are less likely to kill neon tetras in general.

Your Neon Tetras Could Die Due To Stress

Neon tetras are very susceptible to stress, and stress-related death is one of their most common causes. 

Knowing how to look for the signs of stress and managing it in your fish is essential to keeping them healthy, and this becomes especially true with your neon tetras. 

Several factors will impact the stress levels of your neon tetras, and if you notice them, you need to take immediate action, as they could die. 

When you notice your neon tetras frantically swimming up and down the sides of your aquarium, it means they want to get out. Your aquarium may be overcrowded and small, forcing your neon tetras to glass surf. 

Additionally, your neon tetras will hide when they are scared or uncomfortable in their tank. Neon tetras will often get bullied by other types of fish, so you should research the compatibility of your aquarium mates.

Your Neon Tetras Could Die Due To Unexpected Toxins

Even the tiniest amount of toxic contaminants can be fatal to your neon tetras. This includes hand lotion, perfume, cleaning chemicals, and even bug spray. 

If their aquarium’s water becomes contaminated with these substances, your neon tetras will suffer and likely die. 

Before working with your aquarium, be sure to thoroughly wash your hands to get rid of any toxic components. You can also protect your aquarium further by purchasing a tank cover.

Your Neon Tetras Could Die Due To Bad Genetics

This may come as a surprise, but due to neon tetras’ popularity, almost two million of them are sold monthly for home aquarium usage. 

Neon tetras are known worldwide, and many beginners and advanced fish keepers prefer neon tetras and end up breeding them in enormous amounts for selling purposes. 

Some people also reproduce neon tetras in huge fish farms. They are produced in such large amounts that people don’t even have enough time to count how many they are and resort to weighing them. 

During this unethical and crazy breeding process, the quality check is little to none. This is where more and more people will notice deformities such as bent spines in neon tetras. 

Some neon tetras cannot survive for their expected lifetime due to bad genes.

Your Neon Tetras May Die Due To Disease

Although neon tetras have a reputation for being tough fish, one of their primary causes of death is an illness known as neon tetra disease, an ailment that the Microsporidian parasite causes. 

Despite the name, neon tetra disease can also spread to other types of fish, including barbs, angelfish, and rasboras. 

This disease causes difficulty in swimming, cysts discoloration, and restlessness, among many other symptoms. 

Other notable diseases that cause the death of neon tetras include dropsy, hemorrhagic septicemia, mouth fungus, columnar, and velvet disease.


Hopefully, this guide has helped you answer “why are my neon tetras dying?” and provided some helpful solutions to prevent it from happening again. While there are an array of potential culprits, good tank maintenance, and making sure your aquarium has a large enough neon tetra school, are key to caring for these vibrant fish.

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