One of the most common mistakes one could make when treating betta fish is in accurately determining the right dose. It’s essential that you know the level of water should be in the fish tank so you can give the precise amount of medicine. These are some of the signs to look for in sick Bettas; decreased appetite, fins clamped to the sides, scraping body on rocks, abdominal swelling, inflamed or discolored skin or fins, loss of appetite for extended periods of time, lethargic and frequently hiding, dull coloring, especially in males, tattered fins with black edges, white growths on body or mouth, swimming abnormally, labored breathing, clamped fins, and bloated.


Fish Lice (Argulus)

Description: Visible crustacean parasite that feeds and lays eggs on Betta fish

Type: External Parasites     Contagious: Yes


  • Erratic swimming
  • Lice are visible on skin
  • Ulcers
  • Clamped fins


  • Using a pair of tweezers, gently remove the parasite from the Betta fish.
    if large wounds are left behind, use a cotton swab dab 50%  Mercurochrome on the affected area.

Gill/Skin Flukes

Description: Parasites will breed and lash onto any part of your Betta such as the gills, fins, or body.

Type: External Parasites     Contagious: Yes


  • Gasping for air at the waters surface
  • Damage to the gills
  • Gills covered in mucus
  • Scraping
  • Ulcers and wounds


  • This type of parasite is best dealt with by a veterinarian.


Description: Small localized white patche often confused with columnaris, ich, or body slime.

Type: Protozoan   Contagious: Yes


Anchor Worms (Lernea)

Description: Highly visible parasites will lash onto your Betta’s skin

Type: Parasitic     Contagious: Yes


  • Scraping
  • Ulcers/Sores from rubbing against objects
  • Breathing Difficulties
  • Lethargic Behavior


  • To cure anchor worms requires a mix of manual removal, treatment with potassium permanagate, treating the aquarium with salt, and if possible removing your betta to a quarantine tank for a month.
  • The best way to prevent anchor worms is by quarantining all new additions to your tank.


Description: Yellow spots will be found on the body and/or fins of your Betta. Very hard to detect on Yellowish/Gold colored Bettas. Number one killer of betta fish. Make sure to treat the entire fish tank, fish net, and other tools thoroughly. Keep Betta in fish tank in a  dark place during treatment to accelerate recovery.

Type: Parasitic     Contagious: Yes


  • Scratching body against hard objects
  • Fish is lethargic
  • Loss of appetite
  • Rapid, labored breathing
  • Clamped fins
  • Fine yellow or rusty colored film on the skin (giving a velvety appearance)
  • In advanced stages, skin peels off


  • To treat a Betta who has velvet, turn off tank lights, and if possible increase the water temperature up to 30 degrees Celsius because the parasites cannot thrive in these conditions.
  • Once this is done, use a commercial malachite green remedy. It is important to treat all fish in that tank due to velvet being so contagious. Make sure you also clean the tank and fill it with new clean water.

Slime Disease

Description: Characterized by an over production of mucus coating

Type: Parasitic     Contagious: No


  • Include a grey / white to blue looking mucus coat and rapid breathing (gilling).
  • Extreme cases, obvious physical damage to the skin occurs, secondary infections such as fungus and fin rot can develop
  • Weakens immune system


  • Perform frequent daily water changes for up to a week and use malachite green. Also, the use of aqua salt for up to ten days is recommended to cure slime disease.

Hole in Head

Description: Believed to be caused by Hexamita or poor water conditions

Type: Parasite     Contagious: No


  • White Stringy Feces
  • Loss Of Color
  • Loss Of Appetite & Emaciation
  • small holes located in the head


  • To treat a betta hole in the head you’re going to need to get some medication. The preferred medication is dimetridazole, however, if you can’t find any, you can also use metronidazole.When using medication such as this it’s important that you consult a vet or your local aquarium store to make sure you’re using the right doses.

There are two main ways that you can treat your betta. You can either medicate his food, or the water in the tank. In both cases, however, the first thing you should do when you spot any symptoms of illness is moving him to a quarantine tank.

Medicating a tank will affect all living things. Including any fish, plants or bacteria in the tank. So it’s always wise to set up a quarantine tank.

Treating your Betta with food

To treat your betta with food, all you have to do is medicate it before you feed it to him. You should ask a professional about dosages and routine as there are a lot of circumstances that can change the doses.

Although it’s not likely, sometimes your betta will still be eating when he’s suffering from hole in the head. If he is then it normally means that he’s still in the early stages and treatment is more likely to be successful.

Treating the Water

If your betta isn’t eating, then the only other alternative is to treat the water.

If you plan on treating the water it’s even more important that you move your betta to a quarantine tank, as the medicine will spread everywhere.

Once you’ve moved your betta to a quarantine tank you should begin medicating the water. As a general guide, it’s recommended you use 125 mg per 5 gallons of water. However, you should ALWAYS consult a vet or professional beforehand to get the measurements exact. Otherwise, you could end up killing your betta.


Description: White spots will be found on the body and/or fins of your Betta. Very hard to detect on white colored Bettas. Very sensitive to temperature, therefore when you use a heater; increase the temperature of the tank to eighty five Fahrenheit.

Type: Parasitic     Contagious: Yes


  • Small white dots on the body, fins, or gills resembling sugar granules
  • Scratching body against hard objects
  • Fish is lethargic
  • Loss of appetite
  • Clamped fins


Camallanus Worms

Description: best treated this is through medicated fish food

Type: Parasitic     Contagious: Yes


  • Red/Brown worms protruding from their fish cloaca’s or anus


Internal parasites

Description: Best treated with medicated food

Type: Parasitic     Contagious: Yes


  • Lethargic and lazy
  • Losing weight despite a healthy appetite
  • Sporadic swimming and movements
  • White strings of poop



Description: Usually introduced with the addition of live plants or snails

Type: Parasitic     Contagious: Yes


  • Scraping
  • Ulcers/Sores from rubbing against objects
  • Breathing Difficulties
  • Lethargic Behavior
  • small worms hanging from body




Description: Blood poisoning when infection enters the blood. Septicemia is not a disease but rather a symptom of the infection.

Type: Bacterial   Contagious: No


  • Redness or streaks under the scales


Fin / Tail Rot (Melt)

Description: Red/Black edges along the infected areas. Normally due to filthy water or a dirty fish tank. Usually the lost parts of fin or tail will generate.

Type: Bacterial     Contagious: No


  • Inflamed patches on the fins
  • Faded color or discoloration on the edges of the fins,
  • And fraying of the fin or tail
  • Others symptoms include, lethargy and loss of appetite



Description: This is the only fish disease known to be contagious to man. It can be as long as six months prior to show any symptoms of infections. Unfortunately, not just is there no known treatment, but it is very spreadable, lethal to nearly all other sea life, and hard to get rid of. Even using bleach can’t sanitize against it. You will most likely need to dispose of your bowl, tank, net as well as all other gears.

Type: Bacterial     Contagious: Yes


  • Thinness, loss of appetite, and emaciation
  • Grow body deformities such as popeye,
  • suffer from bloated gills and scales,
  • red clamped gills (otherwise known as pine-coning)
  • fin and body rot,
  • red patches on its body and
  • grey lesions along its side
  • Curved spine/crooked skeleton
  • Sluggish movement/lack of movement
  • Eye damage



Description: Bacterial infection of the eyes. Your fish will usually make a complete recovery, however it is likely your fish loses his eye when you notice it too late. If popeye is presented in only one eye, it’s mostly due to injury and not a bacterial infection. Salt baths and 100% daily water changes are recommended.

Type: Bacterial     Contagious: No


  • Bulging swollen eye
  • The eye may also have a thick white ring around it
  • General reactions to illness will also occur, such as loss of appetite and lethargy


Columnaris (Cotton Wool or Mouth Fungus)

Description: Caused by stressful environment or unmaintained water. This diseases causes ragging, fraying of fins that can lead to lesions or ulcers, scales, fins, and gills discoloration. Betta fish can experience difficulty in breathing due to gill infection.

Type: Bacterial    Contagious: Yes


  • Commonly identified when white or grayish spots or patches can also look yellow or orange on the head and all around the fins and gills



Fungal infection

Description: Cotton like growth on fish/eggs

Type: Fungal     Contagious: Yes


  • White blotchy patches on the body and head of the betta
  • Reactions to the illness will also occur, such as a loss of colour, loss of appetite, lethargy or clamped fins



Dropsy (Pineconing)

Description: Organ failure caused by viral diseases, parasites, and/or bacterial disease. Believed to come from giving your fish with contaminated live food, like for instance black worms. A bacterium which spreads this disease is infectious so ensure to separate the sick fish. Sad to say, there is no cure available

Type: Symptom     Contagious: Maybe


  • Grossly swollen belly
  • Scales that stand out with a pinecone-like appearance
  • Eyes that bulge
  • Gills that are pale
  • The anus that becomes red and swollen
  • Feces that are pale and stringy
  • Ulcers on the body, along the lateral line
  • A spine that curved
  • Fins clamped together
  • General lethargy
  • Refusal to eat
  • Swimming near the surface


Gill Hyperplasia

Description: Build-up of cells and inflammation of gills as result of bad water conditions or toxins.

Type: Symptom   Contagious: Maybe


  • Difficulty Breathing
  • Gills swollen open


Swim Bladder Disorder

Description: Caused by Overfeeding/Constipation or internal parasites.

Type: Ailment     Contagious: No


  • Primary involve buoyancy, including sinking to the bottom or floating at the top of the tank, floating upside down or on their side, or struggling to maintain a normal position



Description: Contrary to popular belief not all tumors are genetic especially benign ones which are caused by mutation during cell replication. Benign tumors won’t grow or migrate unlike other tumors. Tumors can be seen on the outside of the  skin. If the tumor is growing internally, swelling and protrusion will be visible.

Type: Possibly Genetics     Contagious: No


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