Angelfish Diseases, Parasites & Remedies

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An important part of knowing how to care for your angelfish is being aware of the signs and symptoms of the various angelfish diseases that can affect your angelfish.

Parasites, bacteria, fungus and various viral infections can all affect your angelfish. Of course, the first line of defense against diseases is offering proper tank conditions for your fish.

Good water conditions coupled with a varied and balanced diet can go a long way in ensuring that your angelfish develop a strong immune system that can ward off many diseases.

In my experience – and I’m sure many other aquarists can back me up on this – prevention is the best medicine there is, but even with the best prevention diseases may still strike sometimes.

When this does happen, it helps to be aware of how each disease manifests itself, so you can spring into action and offer appropriate treatment for your angelfish.

Here are the most common angelfish diseases, parasites, and remedies that you can apply to prevent further damage or the death of your angelfish:

Angelfish Dropsy

Dropsy appears as a result of an underlying infection caused by a bacterium that’s normally available in aquariums but causes problems if the immune system of your angelfish becomes compromised.

As a result of the infection, kidney function can become compromised, which leads to fluid build-up in inside the fish.

Symptoms of angelfish dropsy include:

  • Bloated appearance and protruding eyes;
  • Scales sticking out;
  • Rapid gill breathing;
  • Loss of appetite and lethargy.

As for the remedies to angelfish dropsy, the outlooks aren’t good. If you notice the disease in its advanced stages, there isn’t anything you can do to save the lives of angelfish that are affected.

If you manage to catch the disease in its incipient stages, adding antibacterial medication to their food and treating angelfish in a separate tank, which contains Epsom salts (⅛ teaspoons to 5 gallons ratio) can help draw out some of the excess fluid.

Angelfish Ich / Ick

Angelfish Ich or White Spot Disease appears as tiny outbreaks of white spots dotted across the body of the fish.

The leading cause of ich in angelfish is sudden changes in water temperature and stress.

Alternatively, introducing plants or other fish that already carry the protozoa in a tank with bad water conditions can also lead to Ich in your other angelfish.

Without treatment the disease carries a high mortality rate, therefore, immediate treatment is required.

Symptoms of angelfish Ick include:

  • White spots on the body of your angelfish;
  • Fish rubbing against objects in the tank trying to remove the spots;
  • Folded fins;
  • Difficulty breathing if spots are located on gills;
  • Loss of appetite and disoriented swimming.

Remedies for Ich include:

  • Anti-parasitic medication;
  • Raising water temperature to 86°F;
  • Adding aquarium salt to the water, which can disrupt the fluid regulation if Ich.

When adding antiparasitic medication into the tank, it’s best to remove the carbon filter, because it may absorb the medication.

Angelfish Fin Rot

Angelfish fin rot is a bacterial infection that commonly appears in freshwater aquariums where water conditions are precarious. It attacks the fins and slowly works its way to the base.

Angelfish fin rot can be caused by Flavobacterium Columnare, Pseudomonas, or Aeromonas, all of which may be present in tanks, which aren’t properly cleaned.

Symptoms of angelfish fin rot include:

  • Fins looking like they’ve been shredded;
  • Difficulty swimming if disease is advanced;
  • Milky-white areas if disease spreads to other areas.

Remedies for this disease should involve a complex approach:

  • Assessment of water conditions, followed by tank cleaning and multiple 20-50% water changes;
  • Removing fish that nip at the fins of other fish, rehoming fish if tank is overstocked;
  • Antibiotic treatment.

Unfortunately, once the infection damages the fins of your angelfish, the affected tissue cannot be regrown or regenerated, therefore, I recommend doing your best to prevent the disease from spreading by following a strict treatment plan.

Angelfish Velvet Disease (Gold Dust Disease)

Velvet Disease is an infection caused by the parasite Piscinoodinum, which attacks the body of the fish forming a cyst in the natural slime coating of the angelfish and then erupting through the skin.

Symptoms of velvet disease in angelfish:

  • Body is coated in gold (sometimes green or brown) cysts;
  • Excess slime production;
  • Rapid breathing;
  • Rubbing against objects in the tank;
  • Loss of appetite;
  • General lethargy;
  • Fins kept at side.

Secondary infections because of the weakened immune system of the fish are also common, therefore, the symptoms of velvet disease can be accompanied by symptoms of other infections as well.

Remedies should be applied immediately as you notice symptoms because the disease is extremely contagious, and it can result in the death of your fish.

Treatment options that can help include:

  • Quarantining fish in a hospital tank, which is blacked-out (cover it with a blanket) for 3 weeks and temperature is raised to 82-86°F;
  • Add aquarium salt to the tank (dissolve aquarium salt in 0.5-1 gallon container of warm water, add 2.5 teaspoons of aquarium salt for every gallon of water in your aquarium);
  • Medication added to the tank (e.g. formalin, acriflavin, methylene blue, copper sulfate).

If your angelfish respond to the treatment, they can be transferred from the hospital tank into a suitable aquarium.

Angelfish Hexamita (Hole-in-the-Head Disease)

Also known as Hole-in-the-Head disease, Hexamita is caused by the rapid multiplication of a parasite that’s normally present in freshwater aquariums. Untreated, the disease can cause the death of your angelfish.

Symptoms of angelfish hexamita:

  • Loss of appetite;
  • White, stringy feces;
  • Lesions on the head;
  • Loss of color.

Remedies for angelfish hexamita that can help:

  • Quarantining infected with in a hospital tank;
  • Raising water temperatures gradually until it reaches 90°F;
  • Treating the aquarium with MetroPlex.

Angelfish Gill Flukes

Gill Flukes in angelfish refer to parasitic infections that affect the gills and skin of your fish. Outbreaks are usually caused by stress and improper tank conditions.

Parasites can burrow into the skin of fish and create ulcers and infections.

Symptoms of angelfish gill flukes:

  • Gills look like they’ve been shredded or chewed;
  • Excess mucus formation;
  • Breathing difficulties;
  • Rubbing against objects;
  • Red skin.

Remedies for angelfish gill flukes you should try:

  • Treatment with anti-worm medication Praziquantel.

Angelfish Anchor Worms

Anchor Worms aren’t technically worms. They’re small crustaceans that embed themselves into the scales and flesh of your fish.

Symptoms that can help identify angelfish anchor worm disease:

  • Redness, ulcers, inflammation at the spot where the crustaceans embedded into the body of your fish;
  • Red or white-green worms at the base of fins;
  • Difficult breathing and rubbing against objects.

Remedies that can be helpful:

  • Potassium permanganate bath to kill immature anchor worms that haven’t embedded yet;
  • Use tweezers to remove any embedded anchor worm;
  • Treat the aquarium with Dimilin to kill larvae and any adult anchor worm that hasn’t embedded;
  • Treat aquarium with aquarium salt.

To avoid future infestations, be very careful when adding new fish to the tank or adding plants to the tank as both can carry the worms.

Angelfish Swollen Bellies – Big Stomach

Angelfish with swollen bellies or angelfish with a big stomach may be having symptoms of dropsy, which — as I mentioned at the section about angelfish dropsy — is an infection that damages the kidney function of angelfish and causes fluid build-up inside the fish.

Besides dropsy, there are other conditions that can cause angelfish to have a big stomach or a bloated appearance:

  • Spawning – when the angelfish female is preparing to lay her eggs, her belly will have a swollen appearance;
  • Poor digestion – the narrow bodies of angelfish makes them susceptible to constipation caused by poor digestion (soaking dried flakes in castor oil or glycerol, or feeding them mashed peeled peas can ease indigestion);
  • Sign of kidney problems – a cyst, an infection or lesions can also cause angelfish bellies to swell;
  • Internal parasites – various internal parasites can also cause a bloated appearance.

Therefore, angelfish with swollen bellies may not necessarily be ill (e.g. they may be just preparing to spawn), but it’s important to monitor the situation and see if there are further signs of disease.

If you’re in doubt about what may be causing a swollen belly in your angelfish, make sure to consult a specialist.

Angelfish Mouth Fungus Disease

Angelfish mouth fungus is caused by Flavobacterium columnare, which is a gram-negative bacterium that’s present in aquariums and under normal circumstances, it doesn’t affect fish.

However, since they’re opportunistic bacteria, they’ll enter the body of your angelfish via wounds and establish itself in the wound of angelfish with weakened immune systems.

Symptoms of angelfish mouth fungus include:

  • Fluffy off-white cotton-like threads at the face, gills or mouth;
  • Sores and lesions in advanced cases;
  • Ragged fins;
  • Rapid breathing;
  • Excess mucus production on head, gills.

Remedies that you can try to treat angelfish mouth fungus disease:

  • Antibiotic or antibacterial medication (kanamycin and phenoxyethanol at 100 mg/l of water for 7 days;
  • Adding salt or sodium chloride to the tank (1oz of salt per gallon of water) can help prevent the disease.

Keeping optimal water parameters and regularly cleaning the tank can also help prevent this disease.

Angelfish Virus Infection

Also known as angelfish AIDS, the angelfish virus infection is a devastating and virulent infection that can cause the death of your angelfish in a couple of days after infection.

It’s highly contagious and it’s easily spread from one fish to another.

Symptoms of angelfish virus infection:

  • Weakness, loss of energy;
  • Fins folded against the body;
  • Excess amount of slime production;
  • Fish are usually at the bottom of the tank;
  • Nose slightly pointed up.


Outlooks aren’t good for fish that were infected by the virus, and they usually die off in a couple of days, however, some remedies you can try:

  • Quarantine infected fish in a hospital tank (no lights, sponge filter and UV sterilizer);
  • Treat tank with Seachem Para Guard for 3 days, perform a 10% water change between each treatment;
  • Add Mardel Maracyn to the tank to prevent secondary diseases.

If your angelfish survives the angelfish virus infection, you can move them to an aquarium, however, not with healthy fish as they may still carry the virus for at least 6 months.

Angelfish Popeye Disease

Angelfish Popeye disease is an infection that causes fluid build-up behind the eyes of your fish. It can be triggered by precarious water conditions and even though it carries a very low risk of fatality, it can damage the eye and even cause it to fall out.

Symptoms of Popeye disease in angelfish:

  • Protruding, cloudy eyes;
  • Ruptured eyes that lead to loss of vision.


  • Performing a 50% water change 4-5 days in a row to ensure optimal water conditions;
  • Adding Epsom salt to the water at 1-3 teaspoons/gallon;
  • Antibiotics mixed into food and medications that work for fin rot disease can also help.

Angelfish Cotton Wool Disease

This disease can be caused by a variety of factors like overcrowded tank, low water temperatures or poor water conditions.

Symptoms of angelfish cotton wool disease:

  • Translucent layer that’s expanding on the skin of the fish;
  • Edges of the body may appear bloody (like blood is oozing through the skin).

Remedies for cotton wool disease in angelfish depend on how advanced the disease is. If it’s in an advanced stage, euthanasia is the most compassionate thing you can do at this point.

If you’ve managed to catch the disease early on, you should address the environmental factors in the aquarium (cleaning the tank, performing water changes, rehoming fish in overstocked tanks).

Once these things are taken care of, you should add marine salt to the tank (4 teaspoons/gallon) and treat water with potassium permanganate.

Final Thoughts

These are the most common angelfish diseases that can be caused by bacteria, viruses, or parasites in the tank.

Because some angelfish diseases are so difficult to treat, prevention is key. That said, you should focus on keeping water parameters at optimal levels, performing water changes and tank maintenance on the regular.

Moreover, make sure you feed your fish a healthy diet that meets their nutritional requirements and strengthens their immune system.

And lastly, always be very careful with new fish that you’re introducing to the tank (always quarantine them first!) and with live foods and plants that you’re adding to the tank.

If you’re careful about these things, you can minimize the occurrence of diseases and make sure that the immune system of your angelfish can put up a good fight in case diseases still find their way into the tank.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
Questions and Answers

    Your angelfish has pinecone shaped scales? If yes, then this is dropsy. If it is bloated heavily, then maybe it is a bacterial infection or internal parasite. It is really hard to tell what disease is, with such little information. Send me a picture of your bloated angelfish via the contact form if you want me to take a closer look.

I have an angel fish with orange rings around a white dot. She’s developing more. We are setting up a tank for her. Do you know what she has and how to cure it. I’m really scared.

    How big is the white dot. Does your fish only have this single white spot or multiple? If it has multiple white spots, then it is ich, which can be treated quite easy. If this is the only spot and it is growing, it might be a fungal infection or a tumor. Can you send me a picture of your angelfish?

I’m afraid my 4 yr old angel has tumors. He has a lump on one side of his body midway between his Gill & tail. It pokes out like it might pop, then he also has an enlarged lower abdomen. He doesn’t seem sick & is still eating. Should I be worried. I figured if he had cancer or something there is nothing I can do.

    Hi Helen! It sounds like a tumor, but unfortunately you can’t do much about it. Keep the water clean and make sure that the tumor don’t get infected and other mates are not picking on it. Fish can live with a tumor, but don’t expect to have the same lifespan as healthy angels. You can also take your fish to the vet, but the surgery can cost you a lot and there is no guarantee that the vet will be able to save your fish.

Tim Sharko November 5, 2022 Reply

My angel is swimming
Nose down. Seems to have a floatation problem. It’s a 5 inch veil tail. Looks normal but doesn’t swim upright.

I have a female angel fish that is not acting her happy self. She swims near the bottom of the tank for a second and falls to the bottom. She lies there until she is nipped or bumped by the other fish. I had her in a separate tank, when she was not doing well but she lies at the bottom of that tank and doesn’t move. She is breathing fine. Do you have a clue to what she might have and how I can try to save her. She is my favourite happy little fish that is not so happy anymore🙁

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