As mentioned above foiled is the way to go. I've added assorted vegetables in the packet (broccoli, asparagus, zucchini, etc) and have also used Italian salad dressing. Below is a recipe I have saved for a sauce after the fish is cooked which sounds tasty if your so inclined. I wish I knew the author to credit them:
1) 2lbs striper filets
2) 1half cup clam juice
3) 1cup cream
4) 1 teaspoon worcestershire sauce
5) salt and paprika
6) 2 tablespoon's oil
7) 3 tablespoon's flour
8) 4 tablespoon's butter
9) 1 onion,finely minced
10) 1 small garlic clove
11) 1 tablespoon minced parsley
12) lemon juice to taste.
To the heated oil add the minced onion's and garlic,stirring constantly.allow them to fry but not brown,then place a lid on and cook for ten minutes.
Oil a baking pan and put the bass filet's in it, sprinkling them with the salt pepper and lemon juice.Then spread the cooked onion's and garlic over the filet's.
Heat the clam broth, add 1half cup boiling water with 2 tablespoon's butter, and bake the fish at 375 degrees for twenty minutes or until done.
Heat the milk,melt the other 2 tablespoon's of butter,sift in the flour,and cook together,adding the hot milk,and beat.Then add the seasoning and cream.Lift the fish onto a hot platter, add the liquid under the fish to the sauce,stir in the chopped parsley,pour sauce over the fillet's,and serve at once!!