Just looking in my old Micro book, it looks like a few things can be had from the aquarium. Mycobacterium marinum (which is related to TB), which is apparentely pretty rare - causes a granuloma. Staph and Strep would be more what I would worry about w/open wounds. If you get the urge to drink the aquarium water or something you could be faced w/Salmonella, Aeromonas, Cryptosporidium and a grocery list of others - ahhh...diarrhea :-) WASH YOUR HANDS AFTER PLAYIN' w/the fishies!!