Neon Tetra Disease: Why Are My Tetra Dying?

There is a type of disease that can kill just fish. Just like any other animal, there are diseases that can target species or groups of animal.

So what is this disease that can cause the fish to die? The condition is known as the neon tetra disease and is deadly to many species of fish.

It is caused by a parasite organism that will leech the life out of the fish until the fish finally succumb to it. Unfortunately, there is no 100% effective cure for the disease, infected fish will be infectious to tankmates, so it’s best to remove them as soon as you can.

A dead fish can carry this disease, and later it can spread to the other fish that are kept in the same tank. Aquarium water can remain contagious, which is a concern if you’re sharing equipment between multiple tanks or moving fish between tanks.

The parasitic disease will enter the fish through the mouth and bind to the stomach and the digestive system of the fish, slowly killing the fish from the inside out. The symptoms of this disease will be discussed later on in this article.

Unfortunately many fish will consume dead tank mates, or particles of dead tankmates, ensuring the disease can spread quickly. One lucky point is at least this illness isn’t contagious to humans. So the fish owner can relax and slowly clean up the fish tank without worrying about getting the disease.

Symptoms of Neon Tetra Disease

This video above courtesy of Ryo Watanabe shows a poor Neon Tetra affected by the parasite Pleistophora hyphessobryconis.

There are many signs of this disease, but it can take a bit of experience or past experience to come to a successful conclusion. One of the most common symptoms is your beloved watery friend will start to grow white bumps or cysts over its body. Over time, these little white bumps will grow in size and in number. After a short while of showing this symptom, the fish will die.

Besides, the obvious cysts, less obvious symptoms can include your fish will losing its colors, the brighter the fish is, the easier it is to spot. An exceptionally colorful fish, can all of a sudden look dull and lifeless, which should be easy enough to spot. The disease can eventually turn the fish into a pale opaque white color.

Another point to remember is fish suffering from this disease can also get other diseases like fin rot.

The parasite in the disease will affect the fish from inside out, causing the fish to lose all its energy and thus making the fish to lose its ability to swim. The fish also will start to behave in a weird way that regular fish do not behave in.

This fish will act restlessly and start swimming erratically instead of sticking with their groups. They are also unable to school with other fish in the right way and will look out of place.

Fishes are often social animals, which especially true of Neon Tetra, they will swim in schools and become stressed if not enough tank mates are available. If they are not traveling in a school, it likely means the fish is sick, and could well have neon tetra disease.

Therefore, owners should beware of the several symptoms shown by fish which could well indicate whether the fish has Neon Tetra Disease. Although the owner can’t cure it, the owner can at least remove all dead fishes to avoid the unaffected fish from inadvertently eating them.

It is important to notice these symptoms early so that the affected fish can be removed from the tank into another tank to be monitored or euthanized if required, rather than left to suffer. This is the number one way of preventing the disease from spreading and devasting your aquarium population

Species of Fish Affected by Neon Tetra Disease

The parasite affects Neon Tetra species the most, which as you can imagine is why it’s named Neon Tetra Disease. However, other species also get affected by the parasite, so it is essential to find out if your fish is sick. All of the following species are known the be affected by the Pleistophora hyphessobryconis parasite (Neon Tetra Disease):

  • Angelfish
  • Barbs
  • Rasboras

One of the species that show resistance to this disease is the Cardinal Tetras. There have been studies that this species has some resistance to this illness, but no studies are indicating why.

How to Treat Neon Tetra Disease

Unfortunately for all the fish lovers and fish owners everywhere across the world, there is no known 100% working treatment available for this disease. The minute the fish gets it, it has to be separated from the other fishes before it dies. There is no medication to slow down the epidemic of this disease; thus there is nothing that can be done to cure the fish of Neon Tetra Disease with guaranteed success.

The most common thing to do when you realize the fish is suffering from the Neon Tetra syndrome is to separate them from the school of fish quickly. Make sure that the infected fish is put into another tank so that the disease will not affect the other tank mates.

This will help the healthy fish from suffering the same fate.  In this case, prevention is better than a cure. The owner can’t guarantee a cure for the infected fish, but at least he can stop the other fish from being infected as well.

Other Treatments That Should Be Tried

What if I want to try an anti-bacterial treatment? You might have a sick fish, and you are not sure if it is a Neon Tetra infection, so why not use an anti-bacterial treatment? Even if it could or may not be a Neon Tetra syndrome, there is no harm to try an anti-bacterial treatment for the fish in the tank.

That’s why an anti-bacterial treatment like Melafix treatment should be used to remove any bacteria from the water tank affecting the fish. Keeping a tank full of beautiful colorful and healthy fish needs a lot of work to preserve the tank environment, water as well as the fishes itself. The API Melafix is fast working and effective, and it is relatively inexpensive.

API Melafix Remedy

If you’re unsure if the fish is suffering from Neon Tetra disease, you can always opt for an anti-bacterial remedy like Melafix remedy. It is an excellent remedy, and it is a highly recommended treatment for fish that are suffering from bacterial infections.

There is a high rating for this medicine, and you can try it regardless of whether the fish is suffering from the Neon Tetra syndrome or not. It doesn’t have many side effects, so it is recommended for giving it a try anyway. It can also treat mouth fungus and tail rot, which are common symptoms for fish. It also helps to regenerate fins that have been damaged as well as torn tissue.

This remedy also helps to heal open wounds that are important in not letting the fish get other types of illness and diseases. It is an excellent product because it can be used in fresh water and salt water aquariums – a thing that most bacterial remedies are unable to do. Melafix is also useful as it doesn’t clog up the air pump or the filter, and the PH of the aquarium is unaffected. It also doesn’t change the color of the water. Therefore it has no side effects and helps to cure many symptoms of the fish.

We would still recommend quarantining any fish suspected of being affected by the Neon Tetra parasite and treating both tanks.

How To Prevent Neon Tetra Disease

Until you can determine whether it is Neon Tetra Syndrome or just a common bacterial syndrome. Make sure all the other fishes are healthy and not contaminated by the fish that is ill.

The best thing to do if there is an outbreak is to prevent it from happening, such as making sure that the fishes are healthy at the pet shop before buying them. If the fish have some white spots or the owner suddenly sells them at a significant discount make sure that you observe in order not to purchase home a tank of ill fish.

It would be a disaster if the new fish from the fish shop comes back home and contaminates the entire aquarium. If you have the space to do so, it’s recommended to create a quarantine tank for any new fish.  This will allow you to observe them for a period of time.

Once you’re confident that your new fish are healthy they can be added to your general tank population.

The best way to keep your fish healthy is to keep the aquarium as well as the tank water clean. You need to perform weekly cleaning to ensure the health of your aquarium. Make sure that dead parts of a fish are all removed so that other fish won’t go and eat it and die if they are infected.

Other Ways Neon Tetra Disease Infection Can Occur

The disease can also be communicated via fish food and in particular live foods.  So, what can you do to prevent this? This is a difficult one, but we would suggest only buying fish food from a known source, and don’t catch your own live food!


The fact is you can’t cure the fish that has been contaminated. The only thing is you can quarantine your fish before adding them to the aquarium and also separate them from the new fish that has been detected as ill.

Also, make sure that all new fish are bought at a favorite pet shop or a regular place to avoid buying sick fish that can contaminate the whole tank the minute it lands into the aquarium. Besides, read up on the internet on how to deal with other bacterial symptoms. Always treat your fish well and clean the tank regularly.


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