Tuberculosis in Angelfish

TB is a type of bacteria with an external protective layer or covering that makes it hard to be detected by the fish’s immune system.

This disease may have no visible symptoms at first but over time it can develop various signs such as a sunken belly, enlarged eyes, lethargy, and weakness.

Fish Tuberculosis is a zoonotic disease, meaning it may also be transmitted from pets to humans through open wounds.

Fortunately, there are a few things you can do to keep your fish free of Tuberculosis.

In this article, we’ll take a closer look at TB, what is it, how it develops, and how to cure it.

What Is Fish Tuberculosis?

It’s called Fish Tuberculosis because the mycobacterium responsible for causing it in people produces the same infection in fish as well!

Fish TB is a bacteria that can be found in soil, lakes, and oceans, and it’s capable of infecting mammals, birds, reptiles, and fish alike!

Since this mycobacterium contains several bacterias, it can cause various diseases, some of them are localized infections that only affect certain parts of the body, while others may affect the whole system.

What Causes Fish Tuberculosis?

This illness can quickly spread through seemingly healthy groups of fish. It’s mainly contracted by a non-infected individual consuming infected feces, which they commonly mistake for food and give it a taste.

The disease may be found in the water column, filter media, and ornaments of the tank. Once one fish gets sick with TB, it’s difficult to prevent the spread of infection since there are no early outward symptoms of this disease.

Fish tuberculosis can be introduced to your tank by:

  • Addition of infected plants and other biological materials.
  • Addition of non-symptomatic carriers to the tank.
  • Without appropriate sanitary practices, the hands of infected persons can spread the infection to the tank.

Fish TB Symptoms

The list of symptoms for fish TB can be frustrating and confusing since some of the clinical symptoms of this disease may differ from one fish species to another.

The fact that this disease is chronic progressive means it could take years to develop into a clinically apparent illness. However, If your fish is experiencing more than five of the following symptoms, they have most likely developed fish TB.

Here is a list of the most common fish Tuberculosis symptoms

  • Sunken belly (even if they are eating)
  • Enlarged eyes
  • Lethargy
  • Weakness
  • Loss of appetite leading to anorexia
  • Stringy poop (empty casing from poor appetite)
  • Skin lesions
  • Open sores
  • Bones may stick out due to weightless
  • Wasting flesh
  • Spinal deformities
  • Loss of scales
  • Nodules in the muscles
  • Emaciation
  • Ulcers
  • Organ failure
  • Fin erosion

The examination of fish can reveal white or grey nodules in their liver, heart, and kidney. Skeletal deformities are also possible with this disease; diagnosis is based on clinical signs alongside acid-fast bacteria being found when examining tissue sections from those affected organs. 

How to Prevent Fish Tuberculosis?

Mycobacterium spp. (Fish TB) is one of the most difficult pathogens to detect, even with proper quarantine protocols. Even if you sacrifice a single fish for testing it may not be enough as there are likely still others in your tank harboring illness without showing symptoms themselves. 

The only way to prevent infections is by maintaining strict quarantine procedures for all the newly added fish and plants.

Unlike popular belief, a UV sterilizer cannot be used to treat Mycobacterium spp. because the infection is contained within the fish, where UV radiation cannot reach.

How to Treat Fish TB?

Fish tuberculosis is incurable. The only treatment for it is supportive care, which isn’t particularly helpful. Some infected fish will live for a long time without showing any obvious clinical signs of disease. 

You might observe a pattern of random deaths in your tank without ever being linked to other diseases, fish additions, diet, or other environmental causes, such as water quality.

If any fish in your tank tests positive for tuberculosis, it’s safe to assume all of them have been infected. 

In this case, you should keep that tank as a closed system with no new additions or removals and be sure to take proper biosecurity precautions to prevent further infection to the handler.

Can Humans Be Infected with Fish Tuberculosis?

These mycobacterium species can spread from fish to individuals, which is very unusual.

Fortunately, this condition is curable in humans, but precautions should be followed.

People with weak immune systems or with chronic diseases may find themselves at risk due to their compromised natural defenses against disease-causing organisms like bacteria, viruses, fungus spores, etc.

Fish TB can be transferred through contact with infected water or via any exposed tank equipment. 

So, the best way to stay safe from this disease is by practicing good tank hygiene by achieving the following:

  • Don’t suck on the tip of siphons to pull the water up
  • After every tank interaction, wash your hands.
  • Using a strong cleanser, clean all surfaces near the tank.
  • After every usage, clean down all food containers and fish products.
  • After interacting with the tank, do not put your hands or nails in your mouth.
  • A waterproof plaster can be used to seal all wounds on your hands or arms.

Veterinary Intervention and Testing Procedures

If any fish die in quarantine, your veterinarian should carry out the disposal as soon as possible. Fish tissue decomposes rapidly, thus diagnostic testing must be completed promptly. 

If a fish has passed away hours earlier and been nibbled on by its tank mates, it will not be suitable for diagnosis.

There is no antemortem diagnosis for fish tuberculosis in small fish. Typically, one clinically-ill fish will be killed for histopathology examination in a suspected illness. Coelomic surgery or even laparoscopic surgery can be used to diagnose large fish.

The veterinarian will perform specialized acid-fast staining on the tissue to confirm whether the Mycobacterium spp. are present.

Proper Infected Systems Sanitation 

All porous materials, such as branches or moss, should be discarded, as there is no method to clean these items effectively. 

Sand and small granular substrates may be cleaned, but larger rocks and stones have too many nooks and crannies to be properly cleaned.

Since this bacteria has a particular outer coating, selecting the proper disinfectant is critical. The tank and equipment should be cleaned with a one percent Lysol solution to remove infected systems.

If you don’t have access to the Lysol solution, a two percent bleach soak for the tank is recommended.

Never add Lysol to a system with fish! Make sure that all the infected fish have been moved to the hospital tank.

Last Words

Fishkeepers need to be aware that this illness can happen in their tanks and kill off a population quickly. 

It’s gut-wrenching when you’re trying so hard for something beautiful, then it only ends up being taken away all of the sudden.

This disease also has zoonotic potential, meaning it can also be transmitted to humans, so make sure to follow the necessary precautions to avoid contracting this disease.

We hope you have found the useful information you were looking for.

If you still have any questions, please share them in the comment section below and we will get back to you as soon as possible.