Angelfish and ich

In this post, we will learn a little about the biology of Angelfish and its relationship with the ich disease.

Angelfish and ich

Ich or White Spot Disease is a fish disease that causes little white dots along the fish body. In Angelfish, this disease outbreak is stimulated by variations in water conditions and fish stress.

The contaminant is a protozoan, usually carried into the tank by infected fish or plants. The presence of the protozoan, when associated with poor water conditions provoke the symptoms in the fish. Without quick treatment, this illness can cause fish death. 

What is ich in fish?

Fish ich is a parasitic disease that affects fish. It is caused by a ciliated protozoan called Ichthyophthirius, and its main symptom is the appearance of white dots on the fish’s body. No wonder fish ich is also popularly known as “white spot disease”.

Ich disease

The disease is caused by a protozoan that attacks and invades a fish’s body, fins, and gills. However, the white spots that appear often look like grains of salt or sugar, but each is a tiny parasite.

Ich is very harmful to fish as it can cause breathing and mobility problems, and even death. Once the parasite has fixed itself in the aquarium, it is difficult to control the infestation, as they reproduce very quickly.

If ich is not controlled, there is likely to be a 100% mortality rate of fish in the aquarium. Ich is a very contagious disease. Thus, it would take too long for the other fish in the tank to develop some symptoms.

Diagnosing the disease

In the first stage of the disease, before white spots start to appear, infected fish will exhibit some or all of the following changes in their behaviour:

·      Fish will start scratching on stones and decorative objects;

·      Fish will swim disorderly;

·      Fish’s fins will be folded against the body.

·      Loss of appetite.

When the white spots start to appear, they will still be the size of the head of a small pin. Afterwards, the first spots will appear on the fins and can be seen using direct light. As the disease progresses, spots begin to appear more frequently and in more numbers in the fish’s body. 

If the gills are affected, the fish start reaching the surface of the aquarium much longer than usual. This is because they are starting to have difficulties in breathing and they will try to obtain air from the surface.

Is the Ich disease contagious?

Ich is a highly contagious parasitic infection, meaning it can be passed from one fish to another. This occurs because, after reaching adulthood, the parasite leaves the host fish’s body to reproduce. After breeding, newly formed Ich parasites, in search of their host, can infect other fish in the aquarium. As the infection is contagious, it is essential to quarantine newly arrived fish and aquarium plants in a separate treated tank before the introduction into the main aquarium.

Water Temperature Rise

It is possible to fight parasites by accelerating their biological cycle, thus reducing the window of opportunity for exposure and making medications more effective. Above all, to do this, increase the temperature of the aquarium water to 86 degrees Fahrenheit and cold water aquariums to 71 degrees Fahrenheit. Changes in water temperatures are very efficient in the initial stages of the infection.

What is the life cycle of the Ich parasites?

The Ich parasite has a unique and simple biological cycle. In its free phase, it reproduces. However, in its infectious phase, it feeds on the tissues of infected fish.

In the infectious phase, for example, it crosses the outer layers of the fish’s skin. Therefore, it has no preference for any particular tissue. The parasite can then infect the skin, gills, eyes, or fins tissues.

Once inside the fish’s body, the parasites cause lesions that cannot be easily seen directly. Eventually, these bring the protozoa into contact with the fish’s immune system.

So, when the fish’s defence system reacts in an attempt of stopping the infection, it tries to isolate the parasites by wrapping them in a layer of epithelial cells.

Finally, the reaction, known as epithelial hyperplasia, causes the so-called white spots. Once the parasite is big enough, it leaves the fish and descends to the bottom of the aquarium. The parasite begins to multiply and can generate up to 2,000 new other parasites. The length of the parasite biological cycle will depend on the temperature conditions in the tank.

Antiparasitic Drug

The Ich parasite (Ichthyophthirius multifiliis) can only be tackled by medications at a very specific point in its life cycle. However, the medication can work during what is called the swim phase when the parasite multiplies.

This way, when the infection phase starts, the medication will not have the same effect because the parasites will be inside the fish tissue. Antiparasitic drugs, very common on the market for pets, are the most recommended to be used in these cases, therefore, they must be antibiotics, specifically for anaerobes.

What causes Ich?

·      Sudden changes in aquarium conditions, for example, if the water you use in partial changes has a different temperature than the aquarium water;

·      When you introduce fish that were infected with the protozoan into a poorly maintained aquarium;

·      Introduce decorations or plants that carry parasite cysts; 

How to prevent the ich Disease

It is very easy to avoid ich in an aquarium. Firstly, you can take some basic steps to keep your aquarium healthier and free of this parasite.

–       Maintain pH and temperature levels for the species that inhabit the aquarium, carrying out frequent water changes with suitable conditioners, always keeping the same temperature.

–       Buy fish and plants that come from healthy aquariums and quarantine them for at least two weeks before introducing new fish into the main aquarium.

–       Boil rocks and objects before adding them to the aquarium.

–       Use some disinfectant substances for live plants placing them into the tank.

Ich in Angelfish

Angelfish are quite prone to develop Ich or White spot disease. For this reason, it is important to keep the water quality, water change routine, as well as all the water parameters under control. Having a heater with a thermostat may assist in having a stable water temperature and thus, avoid fish stress and vulnerability to infections.


In this post, we understood a little about the biology of Angelfish and its relationship with the ich disease. Also, we discussed manners to avoid and finish an Ich infection.

If you have any thoughts or doubts, feel free to drop us in a comment below!

Frequently Asked Questions (FAQs): Angelfish and ich

How do I know if my fish has Ich?

The fish will develop white spots along their body, fins, and even gills.  The spots are usually spread all over the body, especially on the fins. When they settle in the gills, they lead to respiratory distress. Additionally, the fish can develop swimming and feeding issues.

How to disinfect aquarium with Ich?

In general, the treatment should be done with 2 grams of salt per litre of water. It must be remembered that the addition of salt must be gradual, mainly if it is a large tank. It is also possible to use antiparasitic remedies and increase the temperature. This would also help you on getting rid of the Ich infection.

How to avoid Ich in fish?

There are some steps you can follow to avoid ich development in your tank. Water quality should be good, as well as circulation and filtration system. Also, the temperature and other parameters should be controlled. Fresh or live food should be from a secure source. New plants and fish should spend some time in quarantine before going into the main tank.

What temperature kills Ich?

An increase in water temperature may help you in fighting Ich disease. Temperatures should be increased to 86 degrees Fahrenheit for warm water fish and to 71 degrees Fahrenheit for cold-water fish.

Why is the fish rubbing itself against the rocks?

Your fish may have some health issues. Several diseases cause this behaviour. For example, the ich disease. For this reason, you should look for more symptoms for a more accurate diagnosis.

How to know if the Angelfish is healthy?

A healthy fish eats vigorously; swim around the aquarium; is active; have colourful and vibrant; fins and tail radiate in all directions like a fan; its scales and body look smooth and clean.


Angelfish Disease, Parasites & Remedies.

Are Angelfish Prone To Ich?

Durborow, R. M., Mitchell, A. J., & Crosby, M. D. (2000). Ich (White Spot Disease). Southern Regional Aquaculture Center.

ABDULLAH-AL MAMUN, M. D., NASREN, S., RATHORE, S. S., & RAHMAN, M. M. (2021). Mass Infection of Ichthyophthirius multifiliis in Two Ornamental Fish and their Control Measures. Annals of Biology, 37(2), 209-214.