I've lived along a lot of the east coast, south of DC. Yeah, that's southern mostly, but I would say fried fish is not only a southern thing. Hell, it's a British thing too. Fried chicken, and everything else, is southern, but I've seen fried fish all over, wherever fish is common.

I don't know if I'd call it the American style, but it's common. The issue is America is a bunch of states. It's like if you tried to combine all the states in the EU to one style.

I think fried is becoming less common in the US though. It definitely isn't my preference, and I think that's increasingly true as time goes on.