Why Is My Angelfish Gasping For Air? (With 5 Solutions)

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Approximately two years ago, I noticed my angelfish struggling for air at the surface of the water.

Initially, I thought it might need food, but it quickly became clear that the fish was experiencing distress.

I discovered that this gasping behavior is a sign of a problem. Fortunately, I found out how to address this issue through a few straightforward measures.

In this article, I will share insights into why angelfish exhibit this behavior, the methods to remedy it, and strategies to prevent its recurrence.

So, let’s dive into the details.

Why Is My Angelfish Gasping?

Angelfish may exhibit air-gasping for a variety of reasons. Here’s what you need to be aware of:

1. Poor Water Quality

Poor water quality is a critical factor that affects the health of angelfish, often leading to gasping as a sign of distress.

When water is not properly maintained, it can quickly become harmful to your fish.

  • Toxic Substance Accumulation: Build-up of waste, uneaten food, and plant debris increases the levels of harmful substances, causing irritation and difficulty in breathing.
  • Unstable pH and Hardness: Fluctuations in pH and water hardness can stress angelfish, leading to gasping as they struggle to adapt to the changing environment.
  • Identification Tip: Regularly check water clarity, odor, and color. Use a water testing kit for accurate readings of pH, hardness, and toxin levels.

2. Low Oxygen Levels

Oxygen depletion in an aquarium is a common issue that can lead to angelfish gasping for air at the water’s surface, where oxygen is more abundant.

  • Poor Aeration and Circulation: Insufficient aeration or water movement reduces oxygen levels, making it harder for angelfish to breathe efficiently.
  • Overstocking and Overfeeding: A high number of fish or excessive feeding can deplete oxygen levels faster than it can be replenished.
  • Identification Tip: Apart from gasping, look for fish staying near water surfaces or air stones. Consider using an oxygen test kit to measure the oxygen level in the tank.

3. Gill Disease or Parasites

Gill diseases or parasites can cause significant respiratory distress in angelfish, making them gasp for air as they struggle to breathe properly.

  • Gill Damage: Parasites like flukes or bacterial infections can damage the gills, reducing the efficiency of oxygen absorption and causing respiratory distress.
  • Impaired Gill Function: Diseases or parasites can cause inflammation or blockages in the gills, severely impacting their ability to function properly.
  • Identification Tip: Look for symptoms like red or swollen gills, excessive mucus, and reduced appetite, alongside gasping behavior, to identify gill issues.

4. High Ammonia or Nitrite Levels

High levels of ammonia or nitrites are toxic to fish and can lead to serious health issues, including gasping for air due to impaired gill function.

  • Toxic Exposure: Ammonia and nitrites directly irritate and burn the gill tissues, making breathing difficult and painful for the angelfish.
  • Reduced Oxygen Uptake: These toxins can diminish the capacity of gills to absorb oxygen, forcing fish to gasp at the water’s surface for more air.
  • Identification Tip: Besides gasping, watch for signs like lethargy, loss of appetite, and red or inflamed gills. Use a water testing kit to monitor ammonia and nitrite levels.

5. Stress or Environmental Changes

Stress caused by environmental changes can lead to erratic breathing patterns in angelfish, including gasping at the water surface.

  • Rapid Environmental Shifts: Sudden changes in temperature, pH, or water hardness can stress angelfish, disrupting their normal breathing pattern.
  • Stress-Induced Behavior: Stress can weaken the immune system of angelfish, making them more susceptible to diseases that affect breathing.
  • Identification Tip: Observe for other stress indicators like hiding, skittish behavior, or refusal to eat, along with gasping, to identify environmental stress issues.

Also Read: Stress In Angelfish

Treating Air-Gasping in Angelfish

If your Angelfish regularly gasps for air, just follow these steps:

1. Improve Water Quality

Maintaining pristine water quality is paramount for treating air-gasping in angelfish.

Clean, well-maintained water reduces stress and prevents diseases that can exacerbate respiratory issues.

  • Regular Water Changes: Change 25-30% of the tank water weekly. This practice dilutes harmful substances and replenishes essential minerals in the aquarium.
  • Effective Filtration System: Install a filter capable of turning over the tank’s total volume at least 4-5 times per hour, ensuring thorough waste removal and water circulation.
  • Frequent Water Testing: Test water parameters weekly using a reliable aquarium test kit. Aim to keep pH levels between 6.8 and 7.8, with hardness around 3-8 dGH for angelfish. I personally use the API Freshwater Master Test Kit (link to Amazon).
  • Debris Removal: Clean the tank regularly to remove detritus, such as uneaten food and decaying plant material, which can deteriorate water quality and increase toxin levels.

Also Read: Angelfish Water Parameters

2. Increase Oxygenation

Proper oxygenation is crucial for the wellbeing of angelfish, particularly when they are gasping for air.

Enhancing oxygen levels in the tank helps ensure that the fish can breathe comfortably.

  • Air Stones or Diffusers: Use an air stone or diffuser with an air pump for a continuous flow of small bubbles to boost water oxygen. My recommendation: Hygger Aquarium Air Stone (link to Amazon).
  • Water Movement: Use water pumps or powerheads to create gentle water circulation, which aids in even oxygen distribution. Ensure the flow is not too strong to stress the angelfish.
  • Surface Agitation: Adjust your filter output to create mild surface agitation, which promotes better gas exchange and increases oxygen levels in the tank.
  • Stocking Density: Keep the aquarium population under control. For angelfish, a good rule of thumb is to allocate about 10 gallons of water per fish to avoid oxygen depletion.

Also Read: Do Angelfish Need A Bubbler?

3. Treat Gill Diseases

Addressing gill diseases is essential for angelfish exhibiting gasping behaviors, as these conditions directly affect their respiratory efficiency.

  • Accurate Diagnosis: Watch for symptoms like red, swollen gills, or excessive mucus. Consult a fish health expert or veterinarian for a precise diagnosis and treatment plan.
  • Appropriate Medication: Administer recommended antiparasitic or antibacterial treatments precisely, following dosage instructions. If unsure of the diagnosis, consider using products like Seachem PolyGuard (link to Amazon).
  • Quarantine Sick Fish: Isolate affected fish in a hospital tank to prevent disease spread and facilitate focused treatment, ensuring water conditions in the quarantine tank match the main aquarium.
  • Maintain Water Quality: Keep the water in the treatment tank clean and stable. Avoid sudden temperature or pH changes to reduce stress on the sick fish.

Also Read: Angelfish Diseases

4. Reduce Ammonia/Nitrite

High levels of ammonia and nitrite are toxic to angelfish and can lead to respiratory distress, making it imperative to reduce these levels in the tank.

  • Efficient Filtration: Ensure your filtration system is adequate for your tank size. Biological filtration is key in converting harmful ammonia and nitrites to less toxic nitrates.
  • Regular Water Testing: Test for ammonia and nitrites regularly, striving to keep ammonia levels at 0 ppm and nitrites as low as possible, ideally under 0.5 ppm.
  • Partial Water Changes: Conduct regular water changes, around 20-25% weekly, to dilute ammonia and nitrite concentrations, especially if they start to rise.
  • Limit Feeding: Overfeeding contributes to waste buildup. Feed your angelfish only as much as they can consume in two minutes, twice a day, to minimize excess food decay.

5. Reduce Stress

Minimizing stress is crucial for the overall health of angelfish, especially when they are showing signs of respiratory distress like gasping.

  • Stable Environment: Keep the aquarium environment stable, with consistent water temperatures between 76-82°F and minimal fluctuations in pH and hardness.
  • Adequate Space: Ensure your angelfish have enough space in the aquarium. A minimum of 10 gallons per angelfish is recommended to avoid overcrowding.
  • Enriched Habitat: Provide a habitat with ample hiding places and plants. This mimics their natural environment and helps reduce stress.
  • Gentle Acclimation: When introducing new fish or after water changes, acclimate your angelfish slowly to prevent shock. Gradually mix tank water with their current water over an hour.

Other Signs Indicating Your Angelfish Is Stressed

Stress in angelfish can manifest in various behaviors and physical signs that are important to recognize.

These signs are crucial indicators of their well-being and can help prevent further health complications.

  • Change in Eating Habits: Stressed angelfish often exhibit reduced appetite or complete refusal to eat. A healthy angelfish should show eagerness during feeding times.
  • Lethargic Behavior: An unusually inactive angelfish, often lingering at the bottom of the tank or in a corner, can be a sign of stress, differing from their typically active nature.
  • Aggressive Actions: Increased aggression towards tank mates, such as chasing or nipping, can indicate stress, especially if this behavior is a change from their usual temperament.
  • Color Changes: Stress can lead to noticeable changes in coloration, such as fading or darkening. Healthy angelfish typically display vibrant and consistent colors.

Also Read: Angelfish Staying At The Top

Preventing Angelfish from Gasping in the Future

Preventing angelfish from gasping in the future involves maintaining a stable and healthy aquarium environment.

Regular monitoring and proactive care are key to ensuring your angelfish remain stress-free and healthy.

  • Consistent Water Quality: Regularly check and maintain water parameters within ideal ranges – pH between 6.8 and 7.8, temperature around 76-82°F, and hardness 3-8 dGH.
  • Adequate Oxygenation: Ensure proper aeration and water circulation in the tank, using air stones or pumps, to keep oxygen levels high and consistent.
  • Routine Maintenance: Perform weekly water changes of about 25-30%, clean filters monthly, and remove debris regularly to prevent toxin build-up and maintain cleanliness.
  • Balanced Diet and Feeding: Feed your angelfish a varied diet and in appropriate amounts – typically what they can consume in two minutes, twice a day, to avoid overfeeding and water quality issues.

Do Angelfish Need Air Bubbles?

Yes, angelfish do benefit from air bubbles in their tank.

Air bubbles from an air stone or similar device help increase oxygen levels in the water, which is essential for the respiratory health of angelfish.

Additionally, the movement and circulation provided by air bubbles can promote a more dynamic and healthy environment in the aquarium.

Also Read: Angelfish Breathing Fast


For quick readers, here’s a short summary:

  • Poor water quality, including toxic substance accumulation and unstable pH, is a major cause of angelfish gasping, indicating distress and harmful environmental conditions.
  • Low oxygen levels due to poor aeration, overstocking, or overfeeding can lead to angelfish gasping for air at the water’s surface, where oxygen is more abundant.
  • Gill diseases or parasites impair angelfish respiration, causing them to gasp for air; symptoms like red or swollen gills and excessive mucus are key indicators.
  • High ammonia or nitrite levels in the tank directly irritate angelfish gills, reducing oxygen uptake and leading to gasping, lethargy, and appetite loss.
  • Stress from rapid environmental changes weakens angelfish immune systems, disrupting normal breathing and resulting in gasping and other stress-related behaviors.