Zoonotic Disease of Pet Fish: Fish Tank Granuloma

What is it?

Mycobacterium marinum, more commonly known as fish tuberculosis or fish tank granuloma in humans, is a chronic progressive fish disease that thrives in closed aquatic systems with high density of fish and warmer waters.

How will I know my fish has it?

Some of the symptoms that you see in a fish infected with this bacteria are: Weight loss, non-healing open ulcers, a distended abdomen, loss of appetite, fin erosion, unusual coloration, pop-eye, spinal deformities, and listless behavior are all possible signs of infection. Unfortunately, it is also possible an infected fish will show no external signs and may die mysteriously.

Can I get sick from this?

Unfortunately the answer is yes, but there are many precautionary efforts that can used to avoid infection of yourself or your family. Mycobacterium marinum can be easily transferable on persons that may have minor cuts on their extremities especially after coming into contact with the aquarium water. The bacterium has a relatively slow growth rate, anywhere from two weeks to four months, and can be particularly fatal to immunocompromised individuals. Some clinical signs that you more commonly see in humans can be anywhere from small bumps, infected or ulcerating lesions, and ascending lymphangitic granulomas. Less common signs can be infected joints to arthritis-like complaints. If any of these signs occur, please contact your physician for a further work-up.

Is there anything I can do at home to help prevent this?

The most effective, simplest task you can do is to keep your hands out of the tank completely. Being that most people do not have the time or money to hire their own private fish tank cleaner, I recommended investing in shoulder length gloves to keep your arms dry when performing hands-on cleaning and manipulating of the tank. If you think you may have a fish that has this please contact your local aquatic veterinarian for more information on treating and preventing this disease from ever entering or even spreading through your fish friends. Some things you can always do in the meantime are to empty your tank and thoroughly clean with bleach: the aquarium, plumbing, pumps, filters, live rock, sand, corals, etc..  After the elimination with bleach routine cleaning is highly advised to keep the bacteria from reinfecting the tank. The last preventative measure that can help prevent you from becoming infected is ALWAYS wash your hands immediately coming into contact with the aquarium water, gloves or not, to help prevent infection from occurring.