Why Is My Angelfish Breathing Fast? (With 5 Solutions)

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I get how stressful it is to see your angelfish breathing fast.

When it first happened to me, I was really worried about my fish. But I found out it’s a usual thing and there are ways to fix it.

Why do angelfish breathe like that? How can you figure out what’s wrong? What should you do and how do you stop it from happening again?

In this article, I’m going to talk all about these things, so you’ll have all the info you need. Let’s start.

Is It Normal for Angelfish to Breathe Heavily?

It’s not normal for angelfish to breathe heavily; this can be a sign of stress or poor water quality.

In healthy conditions, angelfish typically breathe at a rate of about 80 to 120 breaths per minute.

However, this can vary based on water temperature and other environmental factors.

For instance, in warmer water, you might notice their breathing rate slightly increases, as warmer water holds less oxygen.

Why Is My Angelfish Breathing Rapidly?

There could be several reasons behind your angelfish’s rapid breathing. Let’s explore the possible causes:

1. Poor Water Quality

Poor water quality is a common cause of rapid breathing in angelfish. High levels of toxins like ammonia, nitrite, or nitrate can directly impact their respiratory health.

  • Toxic Build-up: Elevated levels of ammonia or nitrites in the tank can damage the gills, leading to increased breathing efforts as the fish struggles to extract enough oxygen.
  • Nitrate Stress: While less toxic than ammonia or nitrites, high nitrates can still cause stress, leading to rapid breathing. Regular water tests can help identify these issues.
  • Identification Tip: Apart from rapid breathing, watch for cloudy water, foul smell, or visible algae growth, indicating poor water quality.

2. Oxygen Deprivation

Oxygen deprivation is another critical factor that can lead to rapid breathing in angelfish. This can happen due to inadequate tank aeration or overcrowding.

  • Insufficient Aeration: Inadequate oxygen levels in the water, often due to poor aeration or filtration, force angelfish to breathe faster to meet their oxygen needs.
  • Overcrowding: Too many fish in a small space can deplete oxygen levels rapidly, causing your angelfish to breathe more quickly.
  • Identification Tip: Look for angelfish frequently rising to the water’s surface to gulp air, a sign of oxygen deprivation.

For a better understanding, here’s a table outlining the relationship between dissolved oxygen levels and survivability in an aquarium setting:

Dissolved Oxygen Levels (mg/L)Survivability
< 3 mg/LVery Low (Immediate action required)
3-4 mg/LLow (Stressful for most fish)
5-6 mg/LModerate (Suitable for many species)
7-8 mg/LHigh (Ideal for most aquarium fish)
> 8 mg/LVery High (Optimal for high oxygen-demand species)

If you’d like to know the precise oxygen levels in your tank, you can easily do this with products like the Monitor DISSOLVED Oxygen Test KIT (linked to Amazon).

3. Stress

Stress in angelfish can be triggered by various factors and often results in rapid breathing as a physiological response.

  • Environmental Stress: Sudden changes in water conditions or aggressive tank mates can cause stress, leading to an increase in breathing rate.
  • Handling Stress: Handling or moving angelfish can also induce stress, reflected in their rapid breathing.
  • Identification Tip: Stress signs include hiding, loss of appetite, or color changes in addition to rapid breathing.

Also Read: Stress In Angelfish

4. Disease or Infection

Diseases or infections, such as bacterial or parasitic infections, can affect an angelfish’s respiratory system, causing rapid breathing.

  • Gill Infections: Bacterial or parasitic infections can inflame the gills, reducing their efficiency and causing an increase in breathing rate.
  • Systemic Illness: A systemic illness can affect the fish’s overall health, leading to increased respiratory effort.
  • Identification Tip: Look for additional symptoms like swollen gills, discoloration, or unusual swimming patterns.

5. Temperature Fluctuations

Angelfish are sensitive to temperature changes, and sudden fluctuations can cause respiratory distress.

  • Cold Water: Cold water can slow down metabolic processes, leading to lethargy and increased breathing effort as the fish struggles to maintain bodily functions.
  • Hot Water: Warm water holds less oxygen, causing angelfish to breathe more rapidly to compensate for the reduced oxygen availability.
  • Identification Tip: Regularly monitor the tank temperature; drastic changes in temperature can be identified by observing the aquarium’s thermometer.

How to Treat Angelfish Exhibiting Heavy Breathing

Fast breathing in angelfish can be concerning, but with the right steps, you can often address this problem. Let’s see what you can do:

1. Improve Water Quality

Good water quality is vital for angelfish health, particularly when they show signs of heavy breathing.

Regular water maintenance and careful monitoring can greatly alleviate respiratory issues.

  • Regular Water Changes: Conduct 20-25% water changes every week to remove toxins like ammonia and nitrites; this helps maintain a balance in water chemistry.
  • Use Water Conditioners: Employ water conditioners to neutralize harmful elements like chlorine in tap water, ensuring it’s safe for angelfish and doesn’t harm their gills. I personally use this Tetra AquaSafe (link to Amazon).
  • Test Water Regularly: Regularly check water parameters like pH, ammonia, nitrite, and nitrate using a reliable aquarium test kit to keep the environment stable. My recommendation: API Freshwater Master Test Kit (link to Amazon).
  • Maintain Filtration System: Keep your filtration system clean and functional; a good filter not only cleans the water but also helps in maintaining a balanced ecosystem.

Also Read: Angelfish Water Parameters

2. Increase Oxygen Levels

Proper oxygenation is crucial, especially when angelfish are breathing heavily. Enhancing tank oxygenation can significantly improve their condition.

  • Add Air Stones or Bubblers: Install these devices to boost water movement and oxygen levels, particularly in larger or densely stocked tanks. I recommend the Hygger Aquarium Air Stone (link to Amazon) for its effectiveness and quiet operation.
  • Improve Water Circulation: Use powerheads or an effective filter to ensure even oxygen distribution, which is particularly important in larger or deeper tanks.
  • Reduce Tank Crowding: Keep the number of fish appropriate to your tank size; overcrowding can deplete oxygen levels and stress the fish.
  • Live Plants: Integrate live aquatic plants; they release oxygen during the day, contributing to a healthier tank environment.

Also Read: Do Angelfish Need A Bubbler?

3. Reduce Stress Factors

Stress can exacerbate breathing issues in angelfish. Identifying and mitigating stressors is key to their wellbeing.

  • Minimize Handling: Limit handling and tank disturbances; frequent changes or movements can stress fish, leading to respiratory issues.
  • Create a Calm Environment: Ensure a peaceful tank environment; avoid placing the aquarium in noisy or high-traffic areas, and provide hiding places for your fish.
  • Consistent Routine: Maintain a consistent care routine, including feeding and maintenance schedules, to provide a stable environment.
  • Monitor Tank Mates: Choose compatible tank mates; aggressive or overly active fish can stress angelfish, impacting their breathing.

For example, here are some fish that are compatible with angelfish:

  • Corydoras Catfish (Corydoras spp.)
  • Dwarf Gourami (Trichogaster lalius)
  • Harlequin Rasbora (Trigonostigma heteromorpha)
  • Rummy Nose Tetra (Hemigrammus rhodostomus)
  • Bristlenose Pleco (Ancistrus cirrhosus)
  • Mollies (Poecilia sphenops)
  • Zebra Danio (Danio rerio)

On the other hand, I would avoid species like:

  • Red Tailed Shark (Epalzeorhynchos bicolor)
  • Jack Dempsey (Rocio octofasciata)
  • Tiger Barb (Puntigrus tetrazona)
  • Convict Cichlid (Amatitlania nigrofasciata)
  • African Cichlids (Various species within the Cichlidae family)
  • Oscar Fish (Astronotus ocellatus)
  • Green Terror (Andinoacara rivulatus)

Also Read: Angelfish Tank Mates

4. Treat Disease or Infection

If heavy breathing is due to disease or infection, prompt treatment is necessary.

  • Identify Symptoms: Look for other signs of illness, like changes in appetite, color, or behavior; this can help in diagnosing the specific problem.
  • Consult a Veterinarian: If unsure, consult an aquatic veterinarian; they can provide specific advice and treatment options.
  • Use Appropriate Medications: Treat with the right medications, such as antibacterials or antiparasitics, as prescribed for the diagnosed condition.
  • Quarantine Sick Fish: Isolate affected fish if possible, to prevent the spread of disease and allow for targeted treatment.

As a bridging treatment, while awaiting a diagnosis, you can use over-the-counter products designed to treat a wide spectrum of diseases, such as Seachem PolyGuard (link to Amazon).

Also Read: Angelfish Diseases

5. Stabilize Water Temperature

Fluctuations in temperature can cause stress and breathing difficulties in angelfish.

  • Use a Reliable Heater: Install a high-quality aquarium heater to maintain a consistent temperature, suitable for angelfish (typically around 76-82°F or 24-28°C).
  • Regular Temperature Checks: Regularly monitor the temperature with an accurate aquarium thermometer to detect any unwanted changes.
  • Gradual Temperature Adjustments: If adjustments are needed, do them gradually over several hours to avoid shocking the fish.
  • Avoid Direct Sunlight: Position the aquarium away from direct sunlight and other heat sources to prevent sudden temperature spikes.

Also Read: Angelfish Temperature Guide

How to Increase Aquarium Oxygen Levels Without Using a Bubbler

If you don’t have the will or time to buy an airstone, there are a few steps you can take to increase the oxygen levels in your tank without one:

1. Short-Term Solutions

In situations where you need to quickly increase oxygen levels in your aquarium without a bubbler, there are a few effective methods you can use.

These solutions are especially useful in emergencies or when dealing with power outages.

  • Partial Water Changes: Replace about 10-15% of the tank water with fresh, dechlorinated water at the same temperature to instantly boost oxygen levels.
  • Increase Surface Agitation: Gently stir the water surface or direct a powerhead towards it to enhance gas exchange and increase oxygen absorption.
  • Use a Battery-Powered Air Pump: In case of power outages, a battery-operated air pump can temporarily replace your regular aeration system to maintain oxygen levels.

Also Read: Angelfish Gasping For Air

2. Long-Term Solutions

For maintaining high oxygen levels in your aquarium over the long term without relying on a bubbler, consider the following sustainable approaches.

  • Plant More Aquatic Plants: Live aquatic plants produce oxygen during the day through photosynthesis, naturally enhancing oxygen levels in the tank.
  • Optimize Tank Circulation: Ensure your tank has good water circulation with a properly positioned filter output or a powerhead, which helps distribute oxygen evenly.
  • Reduce Stocking Density: Keep the number of fish appropriate for your tank size; overstocking can lead to oxygen depletion and increased waste.

Why Is My Angelfish Breathing Fast After a Water Change?

Rapid breathing in angelfish after a water change often indicates stress or shock due to sudden changes in the water environment.

It’s important to ensure that the new water matches the tank’s conditions to minimize stress.

  • Temperature Mismatch: If the new water’s temperature significantly differs from the tank’s, it can shock the fish, causing fast breathing. Ideally, the temperature difference should be within 1-2 degrees.
  • Chemical Imbalance: Sudden changes in pH or chlorine levels can also stress angelfish. It’s crucial to treat tap water with a dechlorinator and match the tank’s pH.
  • Dissolved Oxygen Levels: Newly added water might have different oxygen levels. Ensure proper aeration and oxygenation in the new water before adding it to the tank.
  • Ammonia or Nitrite Spike: Sometimes, a water change can disrupt the biological balance, causing a spike in ammonia or nitrites. Regularly test water parameters after a change.

What Should Be the Water Change Schedule

An optimal water change schedule for an aquarium typically involves replacing 10-20% of the tank water once a week.

This frequency helps maintain stable water conditions and prevents the buildup of harmful substances like ammonia and nitrites.

It’s also important to test the water parameters regularly to ensure the aquarium environment remains healthy for the fish.

Steps to Prevent Rapid Breathing in Angelfish in the Future

To prevent rapid breathing in angelfish, it’s essential to maintain stable and suitable water conditions and minimize stress during routine care.

Proper acclimatization and gradual changes are key to their wellbeing.

  • Gradual Temperature Adjustment: When changing water, gradually adjust the new water to match the tank’s temperature, using a thermometer for accuracy.
  • Consistent Water Chemistry: Use a water test kit to match the pH and hardness of the new water with the existing tank conditions to avoid shocking the fish.
  • Acclimatize Fish Properly: Introduce new water slowly, over several hours if possible, to give your angelfish time to adjust to the new conditions.
  • Regular Maintenance: Regular, smaller water changes (about 10-15% weekly) are less stressful than infrequent, large changes and help maintain a stable environment.

Also Read: Angelfish Making Bubbles


For quick readers, here’s a short summary:

  • Rapid breathing in angelfish indicates stress or poor water quality, requiring checks on water parameters and oxygen levels.
  • Angelfish normally breathe 80-120 times per minute, but this rate increases in warmer water or stressful environments.
  • Common causes of rapid breathing in angelfish are poor water quality, oxygen deprivation, stress, disease, or temperature shifts, each with distinct signs.
  • Treating heavy breathing in angelfish involves improving water quality, increasing oxygen, reducing stress, treating diseases, and stabilizing temperature.
  • Preventing rapid breathing requires stable water conditions, gradual environmental changes, and consistent, moderate water changes for angelfish.