Dry bubbly or dry white is always a safe choice for saltwater fish and more delicate whites are better for freshwater fish.
Grilled: Sauvignon Blanc
Cream sauce: Chardonnay
Sushi: Brut Sparkling or unoaked Chardonnay, Riesling, Sauvignon Blanc
Some soft Merlots and Pinot Noirs work well with meatier fish like Tuna and Salmon (Game fish)