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Why Is My Neon Tetra Not Moving? (With 5 Solutions)

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Neon tetras are among the most popular freshwater aquarium fish, mainly due to their appealing appearance and peaceful temperaments.

However, sometimes they present worrying behaviors. For example, a few months ago, I noticed that one of my neon tetras stopped moving completely.

It was still alive, but it stayed at the bottom and didn’t move. After extensive research, I learned that there are many causes behind this issue, each with its own solution.

Possible Reasons For Inactive Neon Tetras

These are usually the reasons behind a neon tetra that stopped moving entirely:

1. Resting or Sleeping

There’s a common misconception that fish don’t sleep because they’re always moving, but like any living creature, neon tetras need to rest:

  • Sleeping habits: Neon tetras may be resting or sleeping, which can make them appear motionless. These fish lack eyelids, making it challenging to tell if they are asleep.
  • Activity patterns: Neon tetras are diurnal creatures, which means they’re active during the day and sleep at night. If you notice they’re not moving at night, it could be because they’re resting.
  • Different sleeping positions: Neon tetras sometimes sleep near the bottom of the tank or rest in plant leaves. If they are motionless, it might be their resting phase.
  • Tank lights: Bright tank lights can affect the sleep cycle of neon tetras. If the lights are always on, your fish might be stressed and inactive.
  • Change in behavior: If your neon tetra is not moving much during their active period, it could signal a potential issue requiring attention.

Also Read: Why Do My Neon Tetras Stay At The Bottom Of The Tank?

2. Bad Water Conditions

The water quality in your aquarium plays a pivotal role in the well-being of your neon tetra:

  • Inadequate water temperature: Neon tetras thrive in warmer water. If the water temperature drops too low, it can slow their metabolism, causing inactivity.
  • High ammonia levels: Ammonia buildup from fish waste or uneaten food can harm neon tetras, often leading to lethargy and unresponsiveness.
  • Wrong pH levels: Neon tetras prefer slightly acidic water. If the water is too alkaline, it can make them uncomfortable and inactive.
  • Lack of oxygen: Poorly oxygenated water can lead to a lack of energy in your neon tetras, causing them to be less active.
  • Hardness of water: Neon tetras prefer soft water. Hard water can induce stress and lead to decreased movement.

3. Disease

Just like any other living being, neon tetras are also susceptible to diseases, which can greatly impact their activity:

  • Ich disease: Also known as white spot disease, it’s a common condition in neon tetras that can cause lethargy.
  • Neon Tetra disease: This disease can cause a lack of movement, paralysis, and eventually death in neon tetras.
  • Swim bladder disease: If your neon tetra is having trouble swimming or is floating upside down, it may have swim bladder disease.
  • Fungal or bacterial infections: These infections can lead to unusual inactivity or lethargy in your neon tetras.
  • Parasites: Parasitic infections can lead to a decrease in activity, as the neon tetra may feel unwell or uncomfortable.

Also Read: Why Do Neon Tetras Twitch?

4. Stress

Stress could be the underlying reason behind your neon tetra’s unusual stillness or reduced movement:

  • Inadequate Acclimation: When neon tetras don’t have ample time to adjust to a new tank, they might undergo stress which can cause them to become inactive.
  • Tank Overpopulation: While neon tetras thrive in groups, a congested tank can create stress, leading to reduced movement.
  • Hostile Tank Companions: Housing neon tetras with aggressive fish species can incite stress, causing them to remain motionless to evade altercations.
  • Frequent Environmental Shifts: Regular changes in their surroundings, like rearranging the tank setup, can induce stress in your neon tetras, resulting in a lessened activity.
  • High-intensity Noise or Vibrations: Loud sounds or vibrations can intimidate your neon tetras, causing stress and prompting them to seek refuge by hiding or staying still.

Also Read: Stress In Neon Tetras

5. Egg-Carrying

Female neon tetras carrying eggs may behave differently than they normally do:

  • Pregnancy stage: Egg-carrying female neon tetras often become less active, especially as they get closer to laying their eggs.
  • Post-spawning behavior: After laying eggs, female neon tetras may become inactive as they recover from the strenuous process.
  • Overproduction of eggs: Sometimes, a neon tetra may produce too many eggs, which can lead to lethargy and decreased movement.
  • Tank conditions: The condition of the tank, including safety, temperature, and hiding spots, can affect the behavior of egg-carrying neon tetras. If they feel threatened, they may become inactive.

Treating Neon Tetras That Stopped Moving

If your neon tetra is not swimming at all, follow these steps:

1. Addressing Resting Neon Tetras

Recognizing and accommodating the resting patterns of your neon tetra is important for maintaining their well-being:

  • Monitor sleeping habits: Observe your neon tetras to identify their sleeping patterns. If they are active during their typical rest period, there may be a problem.
  • Regulate lighting: Maintain a consistent lighting schedule to mimic natural day-night cycles, promoting healthy rest patterns for your neon tetras.
  • Provide hiding spots: Offering secure hiding spots, like plants or decorations, can help your neon tetras feel safe and promote proper rest.
  • Maintain quiet surroundings: Avoid loud noises or vibrations around the tank, especially during the neon tetras’ rest period, to ensure they can sleep peacefully.
  • Consult a professional: If your neon tetra remains lethargic even during its active phase, it may be wise to consult a fish health expert for guidance.

2. Managing Bad Water Conditions

Ensuring a healthy aquatic environment is key for the vitality and activity levels of your neon tetras:

  • Maintain appropriate temperature: Regularly check the temperature of your tank and make sure it’s kept within the optimal range for neon tetras (around 70-81°F or 21-27°C).
  • Check ammonia levels: Regularly test the water for ammonia and nitrate levels, performing water changes as necessary to keep these within safe limits. To do that, I personally use the API FRESHWATER MASTER TEST (link to Amazon).
  • Monitor pH levels: Maintain the pH within the preferred range for neon tetras (around 6.0-7.0).
  • Ensure good oxygenation: Use air stones, plants, or water filters to enhance oxygenation, helping your neon tetras stay active. My recommendation: Hygger Aquarium Air Stone (link to Amazon).
  • Regulate water hardness: Regularly check the hardness of the water, keeping it within the appropriate range for neon tetras.

Also Read: What Is The Best pH Level For Neon Tetras?

3. Treating Disease In Neon Tetras

Promptly recognizing and addressing disease symptoms can help restore your neon tetra to health: 

  • Quarantine affected fish: If a neon tetra shows signs of disease, move it to a separate quarantine tank to prevent the disease from spreading.
  • Consult a vet: Consult a fish health expert for accurate diagnosis and treatment options.
  • Administer proper medication: Follow the vet’s advice and administer necessary medication for your neon tetras.
  • Maintain tank cleanliness: Regularly clean your aquarium to minimize the risk of diseases.
  • Monitor the fish closely: Keep a close eye on your neon tetras during and after treatment to ensure full recovery.

Also Read: 17 Neon Tetra Diseases & Their Treatments

4. Relieving Stress

Reducing stress levels can significantly improve the health and activity of your neon tetras:

  • Proper acclimation: Ensure proper acclimation when introducing neon tetras to a new tank, gradually adjusting them to the new water conditions.
  • Avoid overcrowding: Maintain an appropriate number of fish in the tank to prevent stress from overcrowding.
  • Minimize environmental changes: Avoid frequent changes to the tank setup to reduce stress for your neon tetras.
  • Create a calming environment: Provide plants, hiding spots, and subdued lighting to create a calm, stress-free environment for your neon tetras.
  • Choose tank mates wisely: House neon tetras with compatible species to avoid aggression and stress.

Generally, when it comes to neon tetras, I suggest avoiding aggressive tank mates like:

  • Oscar (Astronotus ocellatus)
  • Jack Dempsey (Rocio octofasciata)
  • Red Devil Cichlid (Amphilophus labiatus)
  • Green Terror (Andinoacara rivulatus)
  • Tiger Barb (Puntigrus tetrazona)
  • Red-Tailed Shark (Epalzeorhynchos bicolor)
  • African Cichlid (Various species from the Cichlidae family)
  • Blood Parrot Cichlid (Hybrid of various Parrot Cichlid species)

Instead, prioritize peaceful and calm tank mates like:

  • Corydoras Catfish (Corydoras sp.)
  • Guppy (Poecilia reticulata)
  • Cherry Barb (Puntius titteya)
  • Harlequin Rasbora (Trigonostigma heteromorpha)
  • Cardinal Tetra (Paracheirodon axelrodi)
  • Otocinclus Catfish (Otocinclus sp.)
  • Dwarf Gourami (Trichogaster lalius)
  • Ember Tetra (Hyphessobrycon amandae)

Also Read: 19 Great Neon Tetra Tank Mates

5. Assisting Egg-Carrying Tetras

If you suspect that your neon tetra carries eggs, follow these steps:

  • Provide a breeding tank: Consider setting up a separate breeding tank for egg-carrying neon tetras to ensure a peaceful environment.
  • Ensure good tank conditions: Keep the water conditions optimal, providing the right temperature and pH for breeding neon tetras.
  • Monitor egg-laying: Keep a close eye on the egg-laying process to ensure it goes smoothly and doesn’t overly stress the neon tetra.
  • Offer nutritional diet: Provide a high-quality, nutritious diet to support the health of the egg-carrying neon tetra.
  • Protect from other fish: Protect the eggs from other fish in the tank that may eat them, by either removing the eggs or the other fish.

Also Read: Neon Tetra Eggs 101


If your neon tetra isn’t moving, tap on the glass and see how the fish reacts. If it starts moving again, the fish was probably just sleeping or resting.

However, if it continues to be lethargic, you should test the water and eliminate possible underlying illnesses.

If you feel unsure about what to do, always consult an aquatic veterinarian. An expert will be able to offer the most accurate solution for your situation.