Wasting Disease in Fish – What It Is and How To Cope!




Wasting Disease in Fish

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Wasting disease, also known as Fish Tuberculosis, is a disease that affects freshwater fish like Betts, Gourami’s, Tetras, Danios, and Barbs.

Knowing the signs of this disease and what causes it can mean the difference between life and death for your fish.

What Is Wasting Disease?

Wasting disease is a fatal disease that is caused by Mycobacterium. This disease also affects white-tailed deer, mule deer, birds, and reptiles. This is also called fish tuberculosis because Mycobacterium tuberculosis is the disease agent that causes tuberculosis in humans.

Animals contract this disease by eating other dead animals, in this case when fish eat other dead infected fish or eat the debris left behind containing the infectious agent.

Mycobacterium has an outer coating that makes it nearly impossible to treat once the infectious prions are in the animal’s system.

Causes of Wasting Disease

Besides eating a sick animal, there are other ways fish contract wasting disease, these include:

  • Adding non-symptomatic fish to your tank
  • Adding infected plants or other biological materials
  • Transferring straight to the tank from the keeper’s hands

Due to Mycobacterium commonly occurring in nature, if the keeper doesn’t properly sanitize their hands before handling fish, it can easily be transferred to the tank environment.

Symptoms of Wasting Disease

One of the issues in diagnosing fish TB is that the symptoms are the same as for other common illnesses. The illness progresses slowly. It is also contagious. The common symptoms include:

  • Loss of appetite
  • Anemia
  • Swollen belly
  • Bulging eyes
  • Lethargy
  • Loss of color
  • Fin rot
  • Skin lesions
  • Bent spinal column
  • Unexplained death
  • Increased secondary infection

Diagnosis of Wasting Disease

The only way to truly diagnose Fish TB in an infected animal is through necropsy. There will be noticeable nodules on the internal organs of the host animal. This animal disease often goes unnoticed because it is impossible to diagnose.

Treatment of Wasting Disease

Unfortunately, there isn’t an effective treatment for this disease. Some recommend heavy doses of antibiotics, but this disease is very antibiotic-resistant. It also can’t be treated with a UV sterilizer because it lives within the fish body where the light can’t reach.

Some fish can live for a prolonged period of time and show no symptoms. If you’re noticing a long-term pattern of death with no reason behind them, this disease may be the cause.

If any fish test positive for this disease in your aquarium, all fish are treated as infected. Once the tank environment has tested positive, it should be kept as an isolated system. Wear gloves when handling anything from the tank.

Wasting disease is a fatal disease and the best treatment is supportive care or humane euthanasia.

How to Prevent Wasting Disease

The best chance for catching this infection is quarantining any new fish that may be infected with the disease. It’s best to test the fish before adding them to your aquarium setup.

This is one of the most difficult pathogens to detect, even if you follow the recommended quarantine period. The infected fish should be sent for testing to see if the fish indeed has Fish TB. The other healthy fish may also be incubating this illness even if they do not have symptoms.

Other ways to prevent this disease include:

  • Not sharing nets, equipment, or accessories between tanks even if there is no indication of disease
  • Wash your hands with antibacterial soap before doing any tank maintenance.
  • Feed a high-quality diet
  • Use a biological filter with activated carbon and filter wool
  • Perform frequent water changes
  • Quarantine new fish for 4 to 6 weeks
  • Remove infected fish immediately
  • Add Vitamin C-enriched dechlorinate

Is Wasting Disease Contagious to Humans?

Wasting disease is contagious to humans through open wounds that come into contact with infectious prions on tank decorations, from contact with the host animal, or contact with infected water. Infected fish with pointy spines can also introduce disease through punctures in the skin.

In humans, Mycobacterium doesn’t cause serious disease as long as you are healthy. If you are immune compromised through illness, pregnancy, or chronic illness, you may be at higher risk for an infection.

The best way to avoid infection is to use proper aquarium hygiene including:

  • Not sucking on the end of a siphon to move water
  • Wash your hands after touching fish or tank water
  • Clean nearby tank surfaces
  • Clean all tank products and food containers after every use.
  • Cover all wounds with a waterproof plaster

Veterinary Diagnosis and Testing

Wasting Disease in Fish

If you have been experiencing deaths in your tank, it’s best to get a dead and infected fish to the vet to run a diagnostic test. Fish tissue breaks down rapidly, so it’s best to take them in as quickly as possible.

In large fish, coelomic surgery or laparoscopic surgery can reveal granulomas. Smaller fish can be tested through histopathology testing. Acid-fast staining is used to confirm the presence of Mycobacterium.

Proper Sanitation for Infected Aquariums

Any porous materials should be thrown away such as moss or branches. Small substrates like sand can be cleaned but large rocks or stones have too many crevices to clean effectively. Mycobacteria is very resistant to disinfectants.

It’s best to throw away the gravel, substrate, and filter material in an infected tank. Decorations can be cleaned in a bleach soak. Ethyl alcohol and Lysol can also be effective in getting rid of this bacterium, but it takes a longer period of time.

Everything will also need to be rinsed multiple times and it’s best not to use them for a while after cleaning.

Overall, it’s best to throw everything away that you can.

What is Livebearer Disease?

Livebearer disease is a term that describes several different disorders that affect live-bearing fish. Wasting disease, body fungus, shimmies and others are all livebearer diseases.

Livebearers are raised in brackish waters and when they are brought into freshwater aquariums their bodies become immunocompromised which allows for more illness. One fish infects another and another and eventually kills all the fish in their aquarium which is why the outbreak is called livebearer disease by uneducated fish keepers.

Just about any livebearer disease can be prevented from spreading by quarantining new fish and feeding them high-quality foods.

For more information on livebearer disease, watch this video.

What Are Fish Shimmies?

Fish shimmies are a symptom often observed in mollies or other live-bearing fish. The fish rocks its body from side to side in a shimmy-like movement.

Shimmies are caused by:

  • Low water temperatures
  • Low PH
  • Low mineral levels which are shutting down their kidneys and other organs

If your live-bearing fish is shimmying, this can be fixed by providing proper water conditions with A PH of 7 to 8, a water temperature of 76 to 80 degrees Fahrenheit, and increasing the mineral content of the water.


Wasting disease, or fish tuberculosis is a heart-breaking disease for any fish keeper to experience. Treatments aren’t typically effective, and it can be difficult to keep the infection under control. Mycobacterium is found in lakes, rivers, or even on raw fish so it’s best to follow tank protocols when handling fish or doing maintenance.

If your fish become infected with this disease, the best thing you can offer is supportive care or humane euthanasia.

To avoid this terrible disease, quarantine any new fish, keep a clean tank, and be careful handling your fish.

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