Here is something that I have tried a few times and always enjoy. (and its really quick and easy to put together, and doesn't take long to cook)
Preheat the oven to 400 F.
Line a cookie sheet with aluminum foil
Place fish on foil, spread some butter on the fish and then sprinkle with salt,pepper and oregano
Top with veggies of your choice (I did onion slices, diced red pepper and small broccolli florets)
Fold up the foil or put another piece on top and fold the edges over themselves - forming a sealed pocket.
Bake for 15-20 min (depends on how thick a piece of fish you have)
I used ocean perch this week, but any white fish would work well, We buy the bonless, skinless frozen fish fillets. You could experiment with different spices as well and I'm sure a squeeze of lemon juice would also taste good instead of the butter (or in addition to - depending on how healthy you are trying to be:)
Serve with pasta tossed with butter, salt, pepper and sage. (this is really yummy! - and also nice and easy)