The Dark Side of fish tanks

Fish can make great pets, especially for those who don’t have enough room for a cat or dog or don’t have the time to exercise a pet. It’s known that watching fish can calm us and lower our blood pressure, and beautiful tanks with fancy fish and decorations can be the center of attention in homes as well as businesses.

But there is a dark side to fish tanks, as a girl in California discovered the hard way. There’s a type of bacteria, called Mycobacterium marinum, that can infect fish and live in the tank. If your immune system is weakened (from medications or disease) or if you have a skin wound (even a scratch can be enough), you’re at higher risk of being infected with this bacteria.

Although it’s scary to think that a small scratch could become such a problem that a girl could lose her hand over it, it’s no reason to get rid of your fish or toss out the idea of getting fish as pets. Luckily, you can reduce your risk of becoming infected if you follow some simple procedures:

1) use gloves when cleaning your tank;
2) if you have a weakened immune system, have someone else clean out the tank;
3) minimize your direct contact with aquarium water;
4) don’t let children clean the tank – or, if you choose to let a child clean the tank, supervise them and make sure it’s done safely;
5) immediately clean up any aquarium water spills;
6) be very careful handling or touching sharp surfaces, such as rocks, gravel and coral, in the aquarium; and
7) always wash your hands after contact with aquarium water or fish.

Posted in Zoonoses/Shared Disease | Tagged , , , | Permalink


  1. Bryce says:

    While I believe everything this articles says is technically correct, I’m offended by how much it’s intended to scare people.

    I did some research, and there are only about 150 confirmed cases per year in the United States. Measured from 1993 to 1996.

    You’re right that fish tanks have a lot of bacteria and people need to be aware of that if they have a tank, but taking that to possible amputation isn’t reasonable.

  2. Dr. Kimberly May says:

    Bryce, thanks for the feedback. As I said in the post, it’s a scary thing but it is also very preventable. Good common sense and proper hygiene and sanitation are all that are really needed. Unfortunately, some people learn the hard way that overlooking these simple things can be risky.

Leave a Reply

Your email address will not be published. Required fields are marked *

6 − five =

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>