I wouldn't use titanium to cook anything directly on it. It heats unevenly and unless coated with nonstick, the use of which I minimize for health reasons, stuff sticks to it like crazy.

Aluminum foil does the job - I foil wrap fish and put it in the coals of a fire, or on rocks in a pot with an inch of water in the bottom, to cook it. This minimizes cleanup and makes for nicely done, moist fish. Adding lemon juice, garlic powder/parsley or olive oil gives the fish a light hint of flavor. I use either hard anodized aluminum or titanium pots - either works well for the times I can't have a fire.

Aluminum got a bad rap for a while, but the research claiming it was dangerous was debunked a long time ago.

I have a hard anodized nonstick MSR pan - now, nonstick - that is proven to release toxins when overheated. I rarely use it, usually just to cook eggs in frontcountry camping, as eggs don't require high temps to cook.