I remember reading a testimonial on some zapper website, I think it was the parazapper. Some guy had a fish that had a jaw that was being eaten by some fungus. So he stuck the zapper probes in the tank and gave it the "zapper" treatment. Within a few days it had completely killed the fungus, the fish had no jaw but the fungus was no longer eating at it. I'm not recommending this, I just remember reading this and almost falling of my chair in laughter. I couldn't believe a guy actually zapped his fish tank.