Cod fillets usually get either battered and deep fried (rarely) or pan fried in olive oil and butter with different spices depending on mood and whats on hand. Sometimes crushed garlic, sometimes lemon pepper, sometimes a commercial fish rub mix. Cod will bake fine, but I prefer pan fried. I don't use bread crumbs or anything when pan frying. I usually use non salted butter and a no salt lemon/pepper mix - cod doesn't need it to my taste.
Salmon fillets are great on the grill. Skin on of course. Firmer fillets I'll season and cook flesh side down for 5-10 min on medium heat, then turn over to finish skin down. Softer or more delicate fillets go skin down entire time, or if real "weak" I'll cook on a pieces of aluminum foil. Grate needs to be real clean and oiled to keep them from sticking. There's enough in oil in salmon that I use dry spices, no marinades. Have used all kinds of stuff that works well - cajun spices, good old lemon pepper, lemon and dill, various premixed fish rubs. Try a cajun type spice or another mix with paprika in it at least once - its good. Did try one mix that was heavy on the tarragon and didn't really care for that one. For baked salmon lemon, lemon & pepper, Lemon & dill, or all three works pretty good.
Years ago I did cook whole salmon on the grill in sort of a poaching method. Put sliced onions, lemon and pepper in the body cavity. Make a "boat" out of foil large enough for the fish, add enough beer to fill whatever space there is in boat without overflowing, cover fairly tightly with another piece of foil so moisture doesn't all boil out, then put in on the grill for awhile (our timing wasn't real precise - wasn't just the salmon getting beer). We'd probably cook a 4-6 lb salmon a half hour or so over a fairly hot charcoal grill. Definitely wanted to hear it bubbling. Came out pretty good and was an easy way to cook a whole fish - but you do need a few people to help eat.
I go for simple - usually dry spices then on the heat. If I remember I'll put the spices in a half hour or so before cooking.
