Even still, lightning does strike the water sometimes. Why doesn't that kill fish by the thousands? Physics has the answer. Like metal, water is a good conductor, so it encourages the electrical current to travel over its surface rather than delve underneath, the same way a Faraday cage protects its contents from harmful shocks. If a fish surfaces at the wrong moment, it can certainly be hit by lightning. Luckily, most fish spend the majority of their time underwater. People don't, however, which is why you should immediately get out of the water if a storm is approaching.