Here two considerations play a part, firstly the type of fish, is it meaty or light and flaky plus how is it served. Light and flaky fish require a light wine - Albarino or Vinho Verde work well. A slighly meatier fish will go well with Sauvignon Blanc or unoaked Chardonnay. As the fish gets more meaty treat it increasingly like a white meat and pair with the lighter reds and fuller whites often with a little oak. An easy all round option is to stick with a nice glass of fizz! When it comes to the preperation "to cream or not to cream" is the question. Simply put cream hates acid, it will curdle the cream in your stomach as you digest it so stick with a Chardonnay or similar.