Common Angelfish Diseases

The most common angelfish diseases are a white spot disease called Ich, mouth rot resulting from injuries from fights with other fish, and dropsy which can cause fish to swim with a tilt. 

Early detection of your angelfish is vital, like looking for signs of common diseases. Early signs of diseases are a loss of your angelfish’s appetite, changes in their body’s color and shape, and when their swimming is unsteady. A healthy angelfish is alert, swims upright with fins and veils erect, and steadily glides forward without effort.


Common signs that your angelfish is unwell lie in how your fish behaves in water. This can be floating to one side, even hovering in a tilted manner.

The most apparent sign of ill health is the distended shape of your aquarium angelfish’s abdomen. The diagnosis is almost certainly angelfish dropsy.

Also known as ‘bloat,’ angelfish dropsy results in an accumulation of fluids in the gut that distends the stomach. This can also be the consequence of underlying severe diseases.

The causes can be underlying health issues brought on by the following:

  • Infections (bacterial and fungal)
  • Parasites
  • Or liver dysfunctions

The retention of fluids makes the angelfish appear like a blown-up balloon. The bloatedness can also be a result of underlying fatal diseases.

One thing you must remember is that angelfish are quite nervous and that external stresses also impact their health. Angelfish become depressed when alone, and this can increase their anxiety and decrease their lifespan.

This can result in bloatedness, a condition in which an angelfish’s body fills with fluid and can lead to kidney diseases or diseases of the gills.

Angelfish’s bloatedness can also be caused by other factors, and it’s essential that you get a diagnosis on the severity of the condition and that this is done in time.

Three Striped Angelfish in Front of Rocks

Common Symptoms of Angelfish Dropsy

It’s good to be on the lookout to see changes in your angelfish’s behavior and the following symptoms:

  • Inflated Belly
  • Protruding scales
  • Bulging eyes
  • Pale-colored gills
  • Fast breathing
  • Rectal Swelling
  • Red Blotches On Skin And Fins

It’s easy to pick up on the above markers of which the angelfish’s swelling is most apparent. The swelling is from poor elimination (or the retention of fluids).

The distorted or extended shape of the angelfish also pushes the scales outwards.

Common Treatments For Dropsy Or Water-borne Disease

If your angelfish are bloated, have swollen and bulging eyes and pale gills, and show signs of distress or stress and hyperventilating like humans do, check the tank for a clue.

Run a test on the water quality. A good osmotic balance is needed for healthy angelfish (and other fish).

This means that a prescribed amount of salt will balance the tank’s salinity with the fish’s blood salinity and will expel the retained water from the angelfish.

Caring For Sick Angelfish

Other necessary steps to take to ensure your angelfish’s health:

  • Don’t clean out all the water
  • Draw-up a schedule for regular cleans

When your angelfish is ailing, you must clean the water in the tank. But don’t do it all at once. Half of the water at most, and check on the pH level for optimal angelfish health.

Often. veterinarians prescribe antibiotics. Dropsy is often associated with diseases with excessive swelling and organ failure and can be fatal.

Mouth Rot

Angelfish are an aquarium hobbyist’s first choice based on their elegant appearance and the graceful way they move. They’re pretty hardy, too, when it comes to diseases.

It’s, however, not uncommon to see angelfish show aggression and, in bouts of tantrums or anger, attack other fish. The injuries are also known as a ‘cotton mouth.

It’s often only when one looks close-up that one can see an angelfish has been injured. The injury is commonly on an angelfish’s mouth.

The symptoms are usually visible in the fish’s behavior, lethargy, and even a loss of appetite.

The process of healing what’s called ‘angelfish mouth rot’ does not happen overnight. This is as, much like sepsis arises in untreated human wounds, angelfish are susceptible to the growth of a mouth fungus after a fish brawl.

Mouth Rot in angelfish shouldn’t go untreated. Often mouth rot is not noticed immediately, and sometimes it’s only picked up when it’s chronic.

The outward signs of mouth rot are a white fungus growing on the injury spot. The injury results from fish fighting, and the wound gets infected with a bacterial infection.

Treatment is necessary to ensure survival.


Angelfish are prone to diseases that have to be diagnosed and treated promptly. This is also the case with the disease Hexamita.

This disease is the result of a parasite that attacks the angelfish. Many aquarists become aware of the disease when they notice that their pet angelfish show the following:

  • Weight loss
  • Stools increase in frequency
  • Angelfish skin color changes
  • Skin decay is noticeable
  • Hole-like lesions appear

As with all other diseases, the signs need prompt interventions.


Angelfish are hardy, but that doesn’t mean they don’t get diseases.

The white spots on angelfish, a disease called Ich, are from a freshwater parasite, Ichthyophthirius multifiliis. This protozoal parasite infects angelfish and leaves distinctive white spots on the fish’s body and gills.

Ich is a common aquarium fish disease, and angelfish hobbyist takes care to spot signs of the disease early. The good news is that Ich is usually easily treated with commercial preparations.

Common Takes On Disease In Angelfish

Home aquarists know that the critical part of having healthy angelfish is that they have to look for early signs of disease and treatment.

As seen above in the section on the treatment of Dropsy, regularly changing the water in a tank can lower the chance of diseases. So too, when buying new fish, hold back and quarantine the fish before adding these to a tank with an existing angelfish population.

Precautions must be in place to stop harmful parasites, bacteria, and viruses.

Common Diseases Stem From Tank Feeds

Aquarists have noticed that they are complicit in bringing harmful bacteria into tanks that often are the root of diseases. These harmful parasites, bacteria, or viruses are dropped into an angelfish tank when you feed them live food.

Some of the common live angelfish feeds, mostly nutrition-dense, that carry the diseases are these:

  • Live bloodworms
  • Brine shrimp (rich in protein)

Besides live feeds, the water in the bag you buy your angelfish in can be contaminated (with ammonia, for example) and shouldn’t be added to the tank.


Angelfish are sought-after by home aquarium hobbyists who act as guardians of this tropical species in tank captivity. angelfish are anxious, with some of their diseases directly linked to this, but mostly they are hardy fish.

The controlled aquarium environment offers optimal conditions for humans to cause and to get involved in the treatment of diseases related to rearing angelfish in captivity.