Water enemies are weak to lightning to an actual natural process known as Electrolysis. If you run an electric current(in this case, a lightning bolt) through a body of water (i.e. a water elemental), it separates the hydrogen and oxygen of the water into their elements.

People need to stay awake in chemistry class.

As for Naga, fish, etc., The ocean becomes a lightning field. Cooked calamari, anyone?

Sea water isn't alive, though, is it?
Were the water shaped into a sentient being, I can see electricity doing a fair bit of damage.

Been a long time since I did any chemistry, but this doesn't sound right at all.

Electrolysis only occurs when there is a chemical reaction between the electrolyte and electrode, when lighting strikes, there is no electrode, no electrolysis.

The damage from lightning is often from heat, generated when the current has to pass through resistance. If there is little resistance, or it is spread out over a large body, such as in a large body of water, the heat generated is pretty small.

I think there are a few dangers to creatures swimming, The first is that in a very large body of water, swimmers may be the highest object on the surface and so your head is a likely target for a strike. Secondly, in saline waters your body may actually be more conductive than the water, so carry most of the current. Thirdly, the electrical shock to your brain or heart didn't kill you outright, you might be knocked unconscious and drown.

Um, yes, so back to Azeroth. Maybe water elementals have a susceptibility to lightning because the current channels through to their vital organs more efficiently. /shrug

Oh I'm wrong :(, electrolysis doesn't need a reactive electrode. Baldagrim was right, it would occur at the point wherever current leaves on enters the body of water. Back to my chemistry books for me!

I have yet to see flood waters be harmed by a downed power line. The people in the flood waters, on the other hand ...


So deliciously morbid....