The Electric Eel - more evidence against evolution

Not neccesarily. Resistance to electrice shock can have all kinds of benefits. I'm no expert on electric eel lifestyle, though. There, was however, an experiment done which showed that this isn't valid. Two mutations are needed for a certain bacteria to use citrus as a food source. Each mutation is useless alone. However, there is documented proof of bacteria evolving the ability to use citrus in a lab setting, as well as in nature (although it was not observed there directly, as you probably guessed)