Why Are My Neon Tetras Breathing Fast? (With 5 Solutions)

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Catching your neon tetra breathing too fast can be pretty scary. That was at least how I felt when I first saw my little creature breathing heavily for no apparent reason.

A few years ago, I conducted extensive research on the topic and gained a lot of experience while doing so.

In this article, I will show you why neon tetras tend to breathe fast and how to fix this, step-by-step. Let’s get right into it.

Why Are My Neon Tetras Breathing Fast?

1. Low Oxygen

Low oxygen levels in the tank water can often lead to rapid breathing in neon tetras as they struggle to extract the required oxygen. Consider this:

  • Limited Aeration: When a fish tank lacks proper aeration, oxygen levels can plummet. This is especially true in overstocked tanks where the demand for oxygen exceeds supply.
  • Poor Water Flow: Water movement helps oxygenate your tank. Without it, oxygen levels can drop causing your neon tetras to breathe faster to get more oxygen.
  • Lack of Live Plants: Live aquatic plants release oxygen into the water. A tank without enough live plants may not have enough oxygen.
  • Overpopulation: Too many fish in one tank can deplete the oxygen levels, making it hard for all the fish to breathe adequately.
  • Decaying Organic Matter: Rotting plants and uneaten food consume oxygen as they decompose, leaving less available for the fish.

Also Read: Why Are My Neon Tetras Blowing Bubbles?

2. Stress

Stress is a common cause of fast breathing in neon tetras. This could be brought on by various environmental factors or interactions within the tank, causing anxiety and discomfort:

  • Inadequate Habitat: Neon tetras thrive in tanks that mimic their natural habitat. A poorly maintained or set-up tank can cause stress, leading to rapid breathing.
  • Aggression from Tank Mates: If other fish are bullying your tetras, this could cause them significant stress, leading to increased breathing rates.
  • Sudden Changes: Any abrupt change in water temperature, pH, or other parameters can stress your tetras, leading to faster breathing.
  • Improper Handling: Frequent netting and moving can cause stress in neon tetras, causing them to breathe rapidly.
  • Noise and Vibrations: Loud noises or vibrations near the tank can scare the fish, causing stress and rapid breathing.

Also Read: Stress In Neon Tetras

3. Elevated Water Temperature

Neon tetras prefer specific temperature ranges and any deviation, particularly towards higher temperatures, could cause them to breathe more rapidly.

Several issues can contribute to this:

  • Increased Metabolism: Higher temperatures speed up the metabolic rates of fish, making them breathe faster to support increased oxygen demand.
  • Lower Oxygen Solubility: Warm water holds less oxygen than cold water. So, if the water is too warm, it may not contain enough oxygen for your tetras.
  • Thermal Stress: A drastic or rapid increase in temperature can stress neon tetras and lead to faster breathing.
  • Disease Outbreak: Warmer temperatures can spur the growth of harmful bacteria and parasites, which can cause fish to breathe faster.
  • Incorrect Heater Setting: If the heater in the tank is set too high, this can raise the water temperature to a level that’s too hot for your neon tetras.

4. Ammonia Poisoning

Ammonia poisoning is a serious risk factor for neon tetras and one of the primary symptoms is rapid breathing. Consider this:

  • Overfeeding: Uneaten food can decay and release ammonia into the water, leading to ammonia poisoning.
  • Inadequate Filtration: If the tank’s filtration system is not adequately removing waste, ammonia levels can build up.
  • New Tank Syndrome: In newly set up tanks, beneficial bacteria haven’t had time to establish and break down ammonia, leading to high levels.
  • Overstocking: Too many fish in one tank can result in excessive waste, leading to increased ammonia levels.
  • Infrequent Water Changes: Regular water changes are essential to remove toxins. Infrequent changes can lead to ammonia buildup.

Also Read: Neon Tetras Staying At The Top Of The Tank

5. Illness

When neon tetras are ill, their respiratory system might be affected. Infections can lead to rapid breathing as the fish struggle to take in oxygen:

  • Response to Stress: Stress can lead to increased breathing in neon tetras. Illness can cause stress in fish, making their respiratory rate go up.
  • Increased Metabolic Rate: Illness can trigger an elevated metabolic rate, which increases oxygen demand. This leads to faster breathing in an effort to meet this demand.
  • Impact of Water Quality: Sickness can cause fish to be more susceptible to poor water quality, which can negatively affect their breathing. Toxins or low oxygen levels can induce faster breathing.
  • Physical Discomfort or Pain: Just like in humans, physical discomfort or pain in fish can lead to faster breathing. Diseases that cause such conditions can make the tetras breathe faster.
  • Compensatory Mechanism: Lastly, rapid breathing can be a compensatory mechanism to overcome the disease. By breathing faster, the fish tries to increase the oxygen supply to its body to fight off the illness.

How To Treat Neon Tetras That Breathe Fast

Treating neon tetras that breathe fast typically involves one of the following:

1. Managing Oxygen Deficiencies

Ensuring your tetras have enough oxygen is vital for their survival. Here are some ways to manage potential deficiencies:

  • Increase Surface Agitation: More water movement at the surface encourages better oxygen exchange. This can be achieved by adjusting the aquarium filter’s output or adding an air stone. My recommendation: Hygger Aquarium Air Stone (link to Amazon).
  • Increase Plant Life: Live plants can produce oxygen during the day, providing an additional oxygen source for your fish. Make sure the plants are healthy and appropriate for your specific aquarium setup.
  • Reduce Stocking Density: Overcrowded tanks can cause oxygen deficiencies. If your tank is overpopulated, consider rehoming some fish or upgrading to a larger tank.
  • Regular Water Changes: Regular partial water changes (around 25% per week) can help maintain good water quality and oxygen levels.

Also Read: Do Neon Tetras Need A Bubbler?

2. Coping With Stress

Stress can affect the health and behavior of your fish, including their breathing rate. To reduce stress in your neon tetras:

  • Provide a Suitable Environment: This includes providing plenty of hiding places, using appropriate substrate, and maintaining good water quality.
  • Keep Consistent Conditions: Sudden changes in temperature, pH, or other water parameters can stress fish. Try to keep conditions in your tank as stable as possible.
  • Minimize Disturbance: Reduce loud noises, sudden light changes, and unnecessary movement around the tank.
  • Quarantine New Fish: New fish should be quarantined before introducing them to your main tank to prevent the spread of disease.

I would also suggest avoiding aggressive tank mates like:

  • Oscar (Astronotus ocellatus)
  • Jack Dempsey (Rocio octofasciata)
  • Red Devil Cichlid (Amphilophus labiatus)
  • Green Terror (Andinoacara rivulatus)
  • Tiger Oscar (Astronotus ocellatus)
  • Convict Cichlid (Amatitlania nigrofasciata)
  • Flowerhorn Cichlid (Hybrid species, no scientific name)
  • Jaguar Cichlid (Parachromis managuensis)

Instead, stick to docile and peaceful species, like:

  • Corydoras Catfish (Corydoras spp.)
  • Harlequin Rasbora (Trigonostigma heteromorpha)
  • Cherry Barb (Puntius titteya)
  • Endler’s Livebearer (Poecilia wingei)
  • Ember Tetra (Hyphessobrycon amandae)
  • Pygmy Corydoras (Corydoras pygmaeus)
  • Celestial Pearl Danio (Danio margaritatus)
  • Otocinclus Catfish (Otocinclus spp.)

Also Read: 19 Great Neon Tetra Tank Mates

3. Resolving Temperature Spikes

Rapid or extreme changes in water temperature can cause your fish to breathe faster. Here’s how to manage and prevent temperature spikes:

  • Regularly Monitor Temperature: Keep an eye on your tank’s temperature using a reliable aquarium thermometer.
  • Use a Heater Guard: This can prevent the heater from overheating the tank.
  • Turn Off Lights: Lights can heat the water. Turn them off during hot weather, or switch to LED lights which produce less heat.
  • Use Fans or Coolers: If the tank is too warm, you can use a fan to blow across the water surface to promote evaporation and cooling.

Also Read: Neon Tetra Temperature

4. Addressing Ammonia Spikes

Ammonia is toxic to fish and can lead to rapid breathing if not managed correctly. Here’s how to deal with spikes in ammonia levels:

  • Regular Testing: Test your aquarium water for ammonia regularly. Ammonia test kits are available at most pet stores.
  • Immediate Water Changes: If you detect high levels of ammonia, perform a partial water change immediately.
  • Use Ammonia Neutralizers: Commercially available products can temporarily neutralize ammonia, giving you time to address the root cause.
  • Review Feeding Practices: Overfeeding can lead to excess waste and higher ammonia levels. Ensure you are feeding your fish the correct amount.
  • Regular Filter Maintenance: Keeping your filter clean can help it effectively remove ammonia from the water.

5. Managing Illness

Illnesses can also cause your tetras to breathe faster. Here’s how to manage and potentially prevent sickness in your fish:

  • Isolate Sick Fish: If a fish appears sick, move it to a quarantine tank to prevent the disease from spreading.
  • Consult a Vet: A veterinarian who specializes in fish can help diagnose and treat illnesses.
  • Choose the Right Medication: You can find over-the-counter medications for common fish diseases, but it’s important to use them responsibly and as instructed.
  • Improve Overall Health: Maintain good water quality, provide a balanced diet, and minimize stress to improve your fish’s overall health and resistance to disease.

Also Read: 17 Neon Tetra Diseases & Their Treatments


Neon tetras may breathe rapidly for various reasons, including oxygen deficiencies, ammonia spikes, temperature shock, etc.

Acting fast is key when dealing with this issue. It’s important to address the underlying cause promptly to prevent the situation from getting worse.