Question

When lightning strikes the ocean why don't all the fish die

Answer 1

Fish near impact will most likely die. The heat and of course electricity will kill them. Even though water is a good conductor, the charge will not affect fish deeper in the water, and electricity follows the way of the fewest resistance, which water has less than fish. Not completly sure about the explaination but it is something like that

Answer 2

From what i know lightning can strike water and  most likely its something to do with the salt but the fish cot die because they are not conductors