Why Do Tetras Twitch? (Causes, Exceptions, And Cure)

Image of cardinal tetras in an aquarium

Tetras are calm fish with predictable behavior patterns. They rarely display unnatural behavior. So, you may find it alarming if you find your tetra twitching or having spasms. If your fish behaves in such a manner, it deserves prompt attention. So, why do tetras twitch?

Tetras twitch because of various reasons. Twitching can signal an underlying health problem in tetras. It could also be caused by stress from environmental factors or the introduction of a new fish into the tank. Tetras may also twitch when they are being aggressive or while preparing for spawning.

Let’s take a deeper look at this now.

How Does A Twitching Tetra Look?

A twitching tetra fish will rapidly rock its body from side-to-side. It may also shake its head, gasp, or show signs of heavy breathing.

A twitching tetra will usually have an abnormal swimming pattern. You will most likely see it moving in circles and twitching its body in the water.

The tetra may ignore any food that you offer. It may look like it has lost control of its movements.

Related Further Reading:

What Causes Twitching In Tetras?

It is normal for tetras to twitch occasionally. They may display this behavior when they feel aggressive or during spawning. Nonetheless, it is wise to keep an eye on the fish. If the twitching continues for a long time, it’s not normal.

You should keep an eye on the tetra to see if it shows other troubling symptoms like cloudy eyes or bloating. Such symptoms usually suggest a bigger problem. Unless you tackle it promptly, the fish may even die.

To help your fish overcome such a condition, you should figure out what is causing the twitching.

Here are the most likely reasons for tetras to twitch.

1. Changes in water chemistry.

Tetras are very sensitive to water parameters. They prefer to live in mature tanks and do not take well to sudden water changes. Some tetras even lose their bright colors after a water change. Their original color returns only after they adjust to the new water parameters.

Tetras do not handle ammonia spikes or elevated nitrate levels well. They are also vulnerable to changes in the temperature and pH of water. It can stress the fish out and cause them to display abnormal and erratic behavior. Hence, aquarium owners should conduct small and frequent water changes to reduce the stress levels in the fish.

If you notice your tetra fish twitching, check for any recent changes in water parameters. Try to gradually restore the balance in water parameters, and the fish should resume its normal behavior.

You can also consider adding a de-chlorinator to the water if the fish continue to twitch.

2. Stress.

Various factors can stress tetra fish and make them display erratic behavior. If you suddenly transfer a tetra into an aquarium, it will not be able to adjust quickly. The fish may go into shock and start twitching.

Tetras are also not comfortable around new fish. So, if you add them to a new aquarium or introduce new fish into their tank, they may become stressed. The fish may then start twitching.

In such circumstances, you can reduce their stress by limiting the movement in the aquarium. Keeping the lights off is also known to help. It will allow the tetra to adjust better to the new change.

3. Disease.

When tetras are affected by parasitic infections, they may have spasms. Ich is one disease that can cause abnormal behavior. You can suspect ich if your tetra has the following symptoms as well.

  • White spots or lesions on the skin that grow.
  • The fish rubs its body or scratches against surfaces like the rocks and walls of the tank.
  • The gills move very fast as they face difficulties in breathing.

Since ich is very contagious, it is wise to treat your fish as soon as you notice it.

Apart from ich, other microbial diseases can also irritate the fish and trigger spasms. Look out for cloudy eyes, excess slime on the coat, or gasping for air.

If you see any of these symptoms, promptly administer suitable medication. Unless you get the condition under control, you may not be able to save your tetra fish.

Related Further Reading:

When Is Twitching Normal In Tetras?

There are a few circumstances when twitching in tetras is normal. Let us explore these conditions.

1. Spawning behavior.

When tetra fish are mating, the male tetra swims around the female in a square pattern. During this time, he will use short jerky movements to attract her attention. The sudden burst of movement will usually be followed by stillness for a short while.

If your tetras twitching is caused by spawning, it will be momentary. The tetra will resume normal swimming once the mating process is over. You should see the female with eggs shortly after.

Since this type of twitching will be for a short duration, you can differentiate it from twitching due to more serious problems.

2. Aggression.

Tetras are generally pleasant, easygoing fish that do not trouble other types of fish. When you keep them in a large group, they will limit their aggression to their school. However, since they are very small fish, they can be intimidated by other fish.

If you keep more aggressive fish with your tetras, the twitching behavior could be caused by stress. Look out for signs that indicate the other fish are harassing the tetra. It could start twitching because it is in distress.

3. The exception of serape tetras.

Each variety of tetra will have its distinct characteristics. So, what seems like abnormal twitching for one variety may be normal for another.

Take serape tetras for instance. Spastic movements are normal for these fish because they are different from other types of tetras.

Serape tetras do not swim smoothly for long distances. They will instead move in short spurts. These fish will twitch from side to side and show a sputtering movement every few minutes. It is normal behavior for this type of fish and should not cause any alarm.

Related Further Reading:

Is It Possible To Rescue A Twitching Tetra?

With timely intervention, a twitching tetra will usually bounce back to health. However, these animals are very small and have a sensitive immune system. So, whether a twitching tetra will survive or succumb will depend on what is causing this erratic behavior of the fish.

When the water parameters in the tank change, they will show signs of distress. Hence, it is crucial to maintain the stability of the aquarium water.

If tetras start twitching in an established mature tank, immediately check for nitrites, ammonia spikes, pH, change in temperature, and salinity. If you fix the problem quickly, the fish should be fine.

However, if the tetra continues to be sick, it could be another issue. Look for signs of parasitic infections like ich. You can cure most infections in the beginning stages with aquarium salt or suitable medication. However, if you postpone the treatment, the fish can become too sick. It will be impossible to save the tetra once it loses its colors and becomes pale and listless.

If a disease causes twitching, it is wise to quarantine the sick fish. You can prevent the disease from affecting other fish in the tank by separating the affected tetra.

Additionally, removing the fish from the main tank will also make it easier to observe it. You can conveniently administer treatment to the fish in another tank until it recovers.