Arowana Fish Common Diseases and Treatments

Featuring a long body, the Arowana fish is one popular freshwater fish. Generally, Arowana fish are native to Africa, Asia, South America, and Australia. They are one of the most expensive aquarium fish that need careful attention. Otherwise, health issues would appear. In this article, let’s take a look at the arowana common diseases and treatments.

Common arowana diseases

Before we get into the details of arowana diseases, let’s take a quick look at some common arowana diseases.

  • Not Swimming
  • Drop Tails
  • Drop Eyes
  • Cloudy Eyes
  • External Injuries
  • Fin Rot
  • Scales Corrosion
  • Overturned Gills
  • Protruding Scales
  • Parasites
  • Fish Lice
  • Anchor Worm
  • “Red Spot” disease
  • “White Spot” disease (Ich)
  • Rotting Gills disease
  • Swim Bladder disease
  • Herbal Bacterial disease
  • Stomach Ailments

Next, we will cover the causes and symptoms of some common diseases of arowana fish.

Not Swimming


  • Frequent fluctuation of water conditions: Fluctuation of water conditions may be the result of continuous water changes, as well as aquarium filter media cleaning and changes
  • Changes in the living environment: Arowana fish are sensitive to changes in the living environment. For instance, new fish introduction, aquarium equipment replacement, as well as water flow and lighting changes would bring stress to Arowana fish
  • Result of suffering from diseases


Drop Tails


  • No wavemaker in the tank: Arowana fish get less exercise as there is no wavemaker at the bottom of the tank
  • Limited space: For limited room, Arowana fish swim around constrained. Then their tails may drop
  • Downward water flow: The downward water flow in the tank may be a reason for drop tails


  • Split tails

Drop Eyes


  • Diet: The food sink to the bottom of the tank, then arowanas will look down to search for food. Also, excessive fatty food will lead to drop eyes, like the beef heart.
  • Genetics: Drop eyes are more common in some arowanas. For example, the Silver Arowana. Generally, the more active ones may lead to more frequent impacts.


  • Fat accumulation above the eyes
  • Look down diagonally

Cloudy Eyes


  • Polluted aquarium water
  • Improper handling


  • Whitish gray film on the fish’s eyes
  • Moldy eyes
  • Swell eyes covered with blueish-white matter
  • Markings on fish body

External Injuries


  • Fight with other tank mates
  • Hit against rocks, tank lid, driftwood, or other aquarium decorations


  • Injuries on fish bodies, fins, or scales

Fin Rot


  • The result of Gram-negative and aerobic bacteria infection
  • Stress caused by poor water quality, high fish density, incompatible tank mates, or other factors


  • Fin erosion
  • Skin lesion
  • Gill necrosis
  • Loss of appetite
  • Move slowly

Scales Corrosion


  • Poor water quality
  • Fight with other tank mates
  • Bacterial infection
  • Vitamin deficiency


  • Damaged or corroded scales
  • Whitening scales

Overturned Gills


  • Poor water quality: Decaying uneaten food and fish feces will cause poor water quality. Also, high levels of nitrite, nitrate, and ammonia will reduce the oxygen level in the aquarium.
  • Limited space: Without an adequate living room, the gill may become overturned.
  • Water temperature fluctuation: Arowanas are sensitive. Hence, maintaining a stable water temperature is essential.


  • Irregular movement of gills
  • Faster and abnormal breathing
  • Concave gill covers and curly gills
  • Loss of appetite

Protruding Scales


  • Polluted aquarium water
  • Sudden changes in aquarium water temperature


  • Tilted scales
  • Blood at the root of scales

Sick Arowana treatments

In this segment, let’s learn some treatments to deal with sick arowana.

Diseases Arowana Treatments
Not Swimming
  • Maintain stable water quality: Change water regularly and do not change a large amount of water at one time
  • Avoid sudden changes in the living environment
Drop Tails
  • Add an aquarium wave maker at the bottom of the tank
  • Make sure adequate living space
Drop Eyes
  • Change the diet: Feed your Arowanas with floating pellets or live food, then they would not look down all the time
  • Limit the Arowanas’ visual focus: Cover the tank’s sides, and only leave the top side uncovered
Cloudy Eyes
  • Do water changes: Change 30-40 percent of water/Change 20-25 percent of the water every three days
  • Add coarse salt
  • Increase the water temp: Heat the aquarium water to 86-92℉
External Injuries
  • Maintain warm water: keep the water temperature at 88℉
  • Add salt. Just follow the rule “300 grams of salt for 100 liters of water”
Fin Rot
  • Do water changes: Change 20 percent of the aquarium water
  • Add salt. Just follow the rule “300 grams of salt for 100 liters of water”
Scales Corrosion
  • Heat the water: Raise the water temp to 86℉
  • Do water changes: Change 30 percent of the water every two days
  • Apply antibiotic medications
  • Add vitamin
Overturned Gills
  • Do water changes: Change 20 percent of the water every 2–3 days
  • Improve the oxygen level: Add or turn on the aquarium air pump
  • Create strong water flow: Add an aquarium wave maker or water pump
Protruding Scales
  • Do water changes: Change 20-25 percent of the water every 3–4 days
  • Add coarse salt or copper sulfate to the water
  • Improve water temp: Heat the water to 90-94℉
  • Promote the oxygen level in the water

Measures to prevent arowana from sickness

This part will share some measures to prevent arowana fish from sickness.

Maintain great living conditions

You should clean your tank and change the water regularly. Also, monitoring the water parameters is needed. It is essential to maintain stable water temperature and other levels, like pH level.

Reduce the risk of infection

If you want to add new tank mates, it is recommended to quarantine them for several days before introducing them to the tank. It can reduce the risk of disease infection or parasite spread.

Provide adequate nutrition

Provide a balanced diet. However, you should not overfeed. Every time finishing feeding, it is better to remove the uneaten food with a fish net.

Reduce the stress

Actually, water temp fluctuation, overstock, incompatible tank mates, or others may cause stress to Arowana fish. Consequently, just keep in mind – do not overstock. And you should be cautious about introducing new tank mates.

Sum up

To conclude, Arowana fish can produce a lot of waste. And most diseases mentioned above are caused by poor water quality. Hence, it is vital to keep Arowanas in a large tank with great water quality. For additional care guides for Arowana fish, you can read Guide to Take Care Arowana Fish.

Finally, thanks for taking the time and we hope this article helps.

Comments (4)

  1. Hey my aro have like white string,very small on his head.can i know what is that?maybe my aro have injury on head but that very small

    Jan 4, 2024 Reply
    • Hi Hariez,
      It seems your aro was hurt by something, bruised or has a head peeling.
      Search the medicine for aro, mix it with 1% salt water, add to some tank water for a medicinal bath, generally, last about half an hour is enough.
      Or you can also use a cotton swab to soak up the medicine and apply it directly for its head.

      hygger team

      Jan 5, 2024 Reply
  2. There is an skin erosion at the starting point of tail. There is red color also. The fish try to bite there. The wings and tail started to peeling of. So please advice which treatment can i give? Nowadays food intake is very less.

    Aju thomas
    Nov 5, 2023 Reply
    • Hi Aju thomas,
      You can keep the water temperature at 88℉;
      Apply antibiotic medications and add vitamin.
      Keep an eye on the skin and keep less feed.
      If there is no improvement of the skin erosion, please consult a vet for more details.

      hygger team

      Nov 6, 2023 Reply

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