As a responsible aquarium hobbyist, you know how important it is to clean your fish tank regularly. While cleaning the tank may not be the same as scrubbing your bathtub or vacuuming your living room, it is still a chore that you must do on a regular basis. For your fish, the aquarium is their home and its state of cleanliness has a significant impact on their health. When the water in the tank becomes dirty, your fish become stressed and they are more susceptible to contracting disease. For this reason, you must clean your tank on a regular basis by performing routine water changes and cleaning out your filtration system. But did you know that if you don’t take proper precautions, cleaning your fish tank – which is so good for your fish – can actually make you sick?
Bacteria in the Aquarium
Different kinds of bacteria play an important role in the health of your aquarium. Certain bacteria, for example, are responsible for establishing and maintaining the nitrogen cycle in your tank. The nitrogen cycle is the process through which beneficial bacteria break down waste products and toxins and convert them into less harmful substances. This results in higher water quality in the tank and, thus, healthier fish. Other types of bacteria are always present in your aquarium but it isn’t until your fish become stressed or suffer an injury that they become a problem. When a fish suffers an injury to the fin, for example, a secondary infection referred to as “tail rot” is fairly common.
While you may already know that bacteria plays a role in keeping your aquarium healthy, you may not realize that certain types of bacteria found in your tank can actually harm you. A recent study conducted by the Henry Ford Hospital in Detroit revealed that the bacteria Mycobacterium marinum can be found in home aquariums. If you have open cuts, scrapes or sores on your hands when you clean your tank, the bacteria could enter your bloodstream. The danger of this is that the signs of infection may not appear for as long as two to four weeks after exposure – this is how long it takes for the bacteria to incubate inside the body.
About the Infection
The bacteria Mycobacterium marinum is a type of free-living bacteria found in non-chlorinated water like that found in home aquariums. This bacteria has been known to cause opportunistic infections in humans, including a rare disease called aquarium granuloma. In 1926, a scientist by the name of Aronson found and isolated the Mycobacterium marinum bacteria in a fish. It wasn’t until nearly 25 years later, however, that this bacteria was linked to disease in humans. During this time, large outbreaks of the infection were fairly common and were linked to shared swimming pools. Today, these infections are much less common due to improvements in construction and maintenance.
The first case of infection linked to an aquarium was reported in 1962 by Swift and Cohen. Mycobacterium marinum infections are considered an occupational hazard for individuals working in pet stores, but most instances of infection actually occur in the home. The infection can be spread from fish bites or injuries caused by fins, but it most frequently enters the blood stream through broken skin during the handling and cleaning of aquariums. As the cause of the disease becomes better understood, more cases are being recognized and reported throughout the world.
Symptoms and Treatment
A Mycobacterium marinum infection typically causes skin lesions, though, again, those lesions may not appear for as long as two to four weeks after initial contact. In some cases, these lesions are single but they are more commonly found in groups. Typically, these skin lesions manifest as clusters of superficial nodules or papules on the skin of the hands and fingers. Lesions of this variety can be either painful or painless and they sometimes become fluctuant.
Unfortunately, misdiagnosis of the problem is fairly frequent due to the rarity of the disease. It is commonly misdiagnosed as a fungal infection, parasitic infection or cellulitis – in extreme cases it may even be diagnosed as skin tuberculosis or a skin tumor. Once a diagnosis is made, however, it can generally be treated with a course of antibiotics. Surgical intervention may be required in deep or extensive infections. Some of the topical treatments used include minocycline, clarithromycin and ethambutol.
Understanding the risk is your best protection against Mycobacterium marinum infection. Now that you know the bacteria may be present in your aquarium, you can take simple precautions to protect yourself. Always wear rubber gloves when cleaning your tank or handling aquarium equipment – especially if you have open cuts or sores on your hands. If you take the necessary precautions, you should have nothing to worry about so don’t take this as an excuse not to clean your tank!