Why Is My Neon Tetra Not Swimming? Shocking Causes And Solutions

neon tetra not swimming

Neon Tetras are small fishes that look beautiful with their silver body with red lining. These fishes are shoaling and active fish which are bound to give you all the benefits of looking after a pet fish. You will be more than happy and at peace to look at them all day long. However, sometimes they appear to be still. So why is my neon tetra not swimming then? Let’s find out.

Various reasons fall under why your neon tetra might not swim. Some of them are diseases, bad water parameters or conditions, lack of a good nitrogen cycle, poor diets, genetic factors, and many more. 

If you want to know about these things in detail, keep on reading further ahead.

Why Is My Neon Tetra Not Swimming?

Neon tetras tend to be still when they are not in a proper health condition or find it difficult to breathe. Therefore, let us study why your neon tetra is not swimming, as it can be due to the following reasons.

Wrong Water Parameters

The neon tetras were quite hardy species, but as the aquarists have been taking these species captive for a long, they have adapted to the aquarium lifestyle. Unfortunately, the life cycle is decreased due to this, and they rely more on the water parameters to be the perfect range.

Tank Water Cycle

If you are not cycling your tank properly or changing its water frequently every week, then you might see this activity in your neon tetra. Since such activity can cause the ammonia level to rise, neon tetra may find it difficult to breathe. As a result, the oxygen level depletes, and neon tetra shows no activeness in swimming.


Diseases can cause the neon tetra to be still and not swimming in the tank as freely as it does. Out of some, swim bladder disease is the common type that can cause such problems.

If swim bladder disease is the case, it can be due to bacterial and parasitic infection on the fish. Neon tetra may even catch cancer and tuberculosis, which causes such stiffness.


Stress is another factor for such tetras to be inactive. When the fish feels any type of danger or changes in water parameters, they become extremely stressed. In such a case, these fish stop doing their regular activities as usual.

Poor Diet

A poor diet can cause its bladder to bloat. Similarly, these fish become weak and susceptible to diseases if you cannot fulfill their nutrition requirements.

External Factors

Some external factors can also cause stress to outburst in fishes. The neon tetra is no different. Any kind of physical trauma like bad tank mates presence in the tank or a rapid temperature change can cause the neon tetra to be still.

Genetic Factors

If you are doing everything right and still are unable to keep your neon tetra active, your neon tetra might be genetically defective. This means that your poor neon tetra was born with a deformed swim bladder.

Moreover, this condition is even aggravated as these fish grow older. The problem here is the breeding of the neon tetra so that they can carry a certain trait. With the increase in popularity, people want a particular shape and size or color of neon tetra.

Thus, causing the neon tetra to grow in a desirable format can cause genetic deformity in neon tetras. Hence, keeping them afloat and inactive.

What Do I Do To Make My Neon Tetra Active and Healthy?

You can just take care of the causes I mentioned above to make the neon tetra healthy and happy. Some of the ways are mentioned below:

Maintain Water Parameters

As per the best guidance, the neon tetra must live in the following water parameters:

The Temperature of the tank water 68 degrees Fahrenheit to 78 degrees Fahrenheit
The ph of the tank water 5 to 7.5
The hardness of the tank water 1 dGH to 10dGH

Maintain Aquarium Cycle

Aquarium cycle means its nitrogen cycle. The ammonia and nitrite levels in the aquarium must be absolute zero. Similarly, the nitrate levels must be less than 10 ppm. You have to change your water every other week from 20 percent to 25 percent to maintain a good nitrogen cycle.

Quarantine The Diseased Fish

If you find a diseased neon tetra, take it and isolate it into another tank as fast as possible. Then, give it extra care and feed it properly until it feels better.

Good Diet And Nutritious Food

A nutritious diet is pretty important for any living being on earth. The same goes for your beloved neon tetra. For its color to stay as bright as it is, you have to feed it properly. This means you require the best diet with proper balance as well as nutrition.

You can even bring the neon tetra back from the diseases it has been suffering from just by feeding it properly. Some of the good food options are:

Correct Tank Size

The neon tetra needs perfect space for it to roam around. For this, you can add 5 to 6 neon tetras in a 10-gallon tank. You may add an extra gallon for every extra neon tetra you add up.

Schooling Neon Tetras

You shall keep neon tetras in schools of 5 to 6 such that they do not stress. These are schooling fish and can be intimidated by other fish species. You may see that schooling these in groups will make them more comfortable and more active in the tank.

External Factors

The temperature increase or decrease is a major factor for it to be inactive. So, make sure you keep the temperature stable by keeping a heater and a thermometer to check the water temperature.

Moreover, you can add air pumps for more oxygenation, filters for better water quality, and lighting for the correct bio topic aquarium feeling.


You can use plants and decors for the neon tetras to hide and be safe in. In such a way, they can feel comfortable in the small tank they live in and create a better healthy state of mind. Likewise, it will make them feel at home if you add some dried leaves as in their natural habitat.

Frequently Asked Questions

Why Does My Neon Tetra Swim in Circles?

Neon tetras swim abnormally when they are sick. These fish will swim in circles when they do not feel well, making them twitch in the tank water. You might even view that the neon tetra is being more inactive and does not respond to food in such a case.

How Can I Tell If My Neon Tetras Are Sick?

The sick neon tetras show the following signs:

  • Swimming irregularly in the tank
  • Bumping into other fishes
  • Being inactive
  • Swimming to the top for the search for oxygen
  • Swimming upside down
  • Being aggressive
  • Bloated body
  • Not responding to food or not eating at all

Can A Neon Tetra Fish Fight With Other Fish?

Neon tetras are quite the active fish in the fish kingdom. That is why it is hard to differentiate whether they are fighting or playing with their tank mates. But, to be honest, the neon tetras love chasing other fish in the tank.

However, it is not a major concern for the people as they mean no harm. Yes, neon tetras can fight, too, but only if you do not give it the appropriate space it needs. Even when they are mating, the behavior can get a little aggressive. In other times, they are not that aggressive.

Last Words

Thus, you can now understand why your neon tetra might not be swimming. Various factors like water parameters, water quality, stress and diseases, good diet and nutritious food, and external and genetic factors, can cause such behavior. However, there is nothing to worry about.

If you find it out on time, you can still create a better environment for your neon tetra. Thus, making them healthier and happier. In addition, neon tetras are not very difficult to fish to look after.

Small adjustments in the water and food will keep them happy. So, take care of such aspects, and they are sure to make your aquarium beautiful and lively! Happy fishkeeping.

Related article:

  1. How Many Neon Tetras Should You Keep In School?
  2. How To Breed Neon Tetras – A Complete Step By Step Guide
  3. Does water pH level affect neon tetras?
  4. How Long Can Neon Tetras Live Without Food
  5. How To Prepare Best Homemade Neon Tetra Food – DIY Fish Food

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