Actually, marinades work well with fish so long as you don't leave them in the marinade very long. Soy sauce, ginger, vinaigrettes, etc., are frequently used as a base for fish and seafood marinades. Also, ceviche is really nothing more than raw fish or seafood marinated in lime juice with other addtions to taste. When I fry fish I almost always marinate it in buttermilk for a half-hour or so before breading it.
"I’m going to break one of the rules of the trade here. I’m going to tell you some of the secrets of improvisation. Just remember — it’s always a good idea to follow the directions exactly the first time you try a recipe. But from then on, you’re on your own." - James Beard