I contracted "fishkeeper's finger" (aka "swimmer's granuloma", "fish tuberculosis" or "FT") a few years ago. Mycobacterium marinum is common to most tanks [Ed note: it is estimates that 95-100% of wild fish carry the pathogen], but a dreadful infection to get. This is also known as "Fish TB" as it actually is a variety of tuberculosis. Failure to use antibiotics to get 100% cures has enabled this bug to become resistant to all but three known (very expensive) antibiotics. I took 2 Biaxin pills a day for over 6 months to get it down to where my immune system could finish the job. Figure it out at $6 per pill! Beside causing severe pain in my wallet, the damned stuff gave me hideous ulceration on the infected finger, and swollen lymph nodes (with severe pain) all up my right arm. One just below my elbow was the size of a walnut and located exactly where you rest your arm to type or do anything at the workbench. IMHO, there are no circumstances, even for a $50,000 Koi, that justify the use of tetracycline, erythromycin, or any other broad-range (kill everything) antibiotic on fish. You usually cannot dose them adequately through the water, only by injection. [Even most vets don't know how to do that correctly.] The bug you may not completely kill is usually not the one you diagnose, but a quiet bystander in the aquarium water -- like my Fish TB was. Antibiotics will not end a sore throat more quickly (except maybe by placebo effect) and can't kill any known virus. Using too little, or for too short a time, just creates resistant bugs. In a given situation, only a trained MD or vet will get it right, and a lot of them don't. [I once knew an alcoholic MD who prescribed tetracycline for every patient he saw. Didn't matter what their problem was, as he was worthless as a diagnostician, so he just gave it to them for anything from a sprain to a headache. GRRRR!] May anyone who uses erythromycin to kill blue-green algae ("BGA") have a trip to the hospital where they get the resistant forms of staph or some other flesh-melting germ. IMNSHO, that's exactly what they deserve for such irresponsibility. BGA is trivially easy to cure, without producing any more resistant *Staphylococcus aureus* Wright Huntley |