How Do Angelfish Breathe?

Angelfish use their gills for breathing, just like any other species of fish. Angelfish breathe dissolved oxygen found in the aquarium’s water. 

Angelfish cannot breathe out of water because they lack the function of taking in pure oxygen and having it travel through the bloodstream. This article includes some of the frequently asked questions relating to the breathing process of Angelfish.

What Is The Breathing Method Of An Angelfish?

The breathing process of an Angelfish involves taking in water through the mouth and passing it through the gills, which are filled with blood vessels. Angelfish use the same breathing method as other fish species.

These gills are made up of blood vessels that carry red blood cells. The gills of the Angelfish have the responsibility to extract oxygen from the water and transfer it to the cells of the Angelfish.

This is how an Angelfish can breathe dissolved oxygen and allow carbon dioxide to be released back into the water.

The lifespan of an Angelfish is usually determined by the ability of the Angelfish to breathe. Breathing problems typically occur when there isn’t enough dissolved oxygen in the aquarium.

Angelfish can suffer from major respiratory (breathing) distress when oxygen levels are imbalanced. These breathing problems can also result in the Angelfish becoming stressed, and this leads to an unhealthy immune system.

White Angelfish with Green and Pink Plants

What Causes Breathing Problems For My Angelfish?

One of the main reasons that contribute to an Angelfish having breathing problems is improper water conditions. Therefore, an aquarium needs to have balanced water conditions that are suitable for the Angelfish.

The aquarium also needs the correct amount of dissolved oxygen so the Angelfish can breathe smoothly. Water pumps are used to increase the amount of oxygen in the water.

Angelfish usually have breathing problems when there is an imbalance in the water PH level and temperature. Other factors, such as an imbalance of nitrate and ammonia levels, also contribute to breathing problems for the Angelfish.

The longer there is an imbalance in the water, the longer the Angelfish will experience respiratory distress. In addition, incorrect water conditions can cause chemicals to damage the angelfish gills, leading to more breathing problems.

Sicknesses and weak immune systems are other factors that also contribute to disrupted breathing for Angelfish. Angelfish that are sick are usually too weak to process the oxygen in the water.

Angelfish tend to lose their color and appetite when they are not receiving enough oxygen. In addition, weak immune systems cause gills to suffer, leading to breathing problems for the Angelfish.

Why Is My Angelfish Breathing Fast?

An Angelfish usually breathes fast when there is a lack of dissolved oxygen in the tank or when the Angelfish is under stress. Angelfish tend to find breathing much more difficult when their immune system and gills are not functioning correctly.

Fast breathing is not a good sign; therefore, you would need to change the water conditions.

Here are a few ways in which you can check if your Angelfish is breathing correctly or not:

  • Check gills to see how fast they are moving.
  • Check how often the Angelfish goes to the surface for air.
  • Check how fast the Angelfish closes and opens its mouth.
  • Check the behavior of the Angelfish while it is gasping for air.

What Can I Do To Ensure That My Angelfish Is Breathing Properly?

One of the first things you would need to do is check the behavior of the Angelfish. The behavior of the Angelfish should tell you if the fish is happy or whether there are some oxygen problems.

Check how fast the Angelfish swims, the breathing patterns, and if the Angelfish is eating. One thing you can also check for is the coloration of the Angelfish.

Another way in which you can check if the Angelfish is breathing correctly is by doing water oxygen level tests. You can use a chemical test kit or a portable dissolved oxygen meter to check the oxygen level in the water.

This process is considered the most accurate way to check whether the Angelfish is breathing correctly. An Angelfish will live a happier life once the amount of dissolved oxygen is in the water.

There are a few other ways to increase dissolved oxygen levels in your aquarium. However, the most common way to increase the oxygen flow in an aquarium is by using a water pump.

Below are other ways in which you can ensure that your Angelfish is breathing correctly:

  • Increase airflow by removing the lid of the aquarium.
  • Ventilate the water by taking water out and throwing it back into the aquarium.
  • Replace water with fresh air that is rich in oxygen.
  • Increase dissolved oxygen levels by removing bacteria, food, and waste in the aquarium.
  • Install an air stone machine that creates bubbles that help with dissolving oxygen.

What Will Happen If My Angelfish Is Not Breathing Properly?

When Angelfish cannot breathe correctly, it means there is either a lack of dissolved oxygen in the water or the gills of the Angelfish might be damaged. When Angelfish cannot breathe properly, they become distressed, which is when their immune systems become weak.

Angelfish tend to lose their appetite when they cannot breathe properly. Stress, a weak immune system, and loss of appetite contribute to the death of the Angelfish.

In addition, Angelfish also tend to become aggressive when there is a lack of dissolved oxygen in the aquarium. This aggressive behavior can be problematic if other fish are in the same aquarium.

However, Angelfish do not die by drowning; they die because of suffocation. This is usually because there is a lack of dissolved oxygen in the aquarium.


Like all fish species, Angelfish breathe by using their gills. These gills are made up of blood vessels that extract oxygen from the water, allowing the Angelfish to breathe. Angelfish depend on dissolved oxygen in the water to thrive and survive. Therefore, angelfish experience breathing problems when there is an incorrect balance of the water conditions in the aquarium.