HOWEVER the species which attack fish are different. They include Mycobacterium marinum (which is widespread in Asian fish farms and is commonly found in imported ornamental fish from those sources). Other species of mycobacterium that commonly infect aquarium fishes include M. fortuitum, and M. chelonei.

Ulcers, open sores and bleeding under the skin are signs of fish TB. The difference between fish TB and most other bacterial related fish diseases is that the fish with the fish TB, 99.99 % of the time, do not get better!

I have taken that from Andrew Tappin's Home of the Rainbowfish. Specifically look at (and please do read) http://members.optushome.com.au/chelmon/Myco.htm

Although it is a bacteria, it is just about impossible to cure and might as well be treated as a virus. Those bacteria are commonly found in aquaria. Usually they have a benign cycle in the mulm in the bottom of tanks. When water quality gets bad, they multiply and can attack the fish. Rainbowfish, for some reason are particularly vulnerable, and if it gets going in a rainbowfish tanks, it is not unknown for the keeper to destroy everything in that tank, bag the fish and plant remains, along with the gravel, and put them in the garbage. (Better a land fill than local streams.) Tanks and equipment are bleached and then rubbed down with rubbing alcohol, which breaks down the waxy membrane, which those bacteria have.

It is possible for those forms of TB to infect aquarists if they have cuts or open sores. Those bacteria do best in the 70s F/21-27 C. That means we might catch it in our hands or arms, because those extremities would be cooler than our torsos.

I have admitted to finding the callous-like growth on that back of one of my hands about 20 years ago. It was slowly growing and I knew I would have to see my doctor about it soon. As "luck" would have it, I had a horrible ear infection and when treated with one of the newer drugs for that, both my ears and hand cleared up! (It - not my case - was written up in the AMA journal in the middle 1970s.) Theoretically if one procrastinated long enough, surgery might be necessary.

Somebody in their 20s or 30s will usually heal up pretty quickly. I would not be so confident now. The immune systems of humans, just like those of fish, are less effective as one gets older. I know of an aquarist in his 70s who contacted fish TB. And he is one of the savvy "grant old-timers of the hobby." It took six months of antibiotic treatment to clear him up! (Cha-ching!)

Since then I have been careful not to put hands with cuts into the water. If I get a nick there, I move fairly quickly to the bathroom sink and irrigate the cut with hydrogen peroxide. I stay out of the water until some healing has taken place. (What some people will do to avoid making water changes!)

I think it is appropriate that Angelhologram should raise the question of fish TB. I'm really glad she knows of it. With her prickly pear cactus spines in her hand, she knows not to put her hand in an aquarium! And so her title "Totally not fish related...need help" is not quite accurate, because open wounds in aquarium (or river or lake) water can have consequences, which we have to deal with.

I would dare say that there are far more diseases we can get from, or share with, warm-blooded pets or even reptiles, One still should be careful around fish. Not paranoid, just careful - sort of like looking both ways when crossing a street. :)