30 minutes at temperature is too long for any fish IMO.

I don't bake it, I grill it, and it turns out pretty damn good with this recipe.

1 clove garlic, minced
6 tablespoons olive oil
1 teaspoon dried basil
1 teaspoon salt
1 teaspoon ground black pepper
1 whole lemon, juiced
1 tablespoon chopped fresh parsley
2 (6 ounce) fillets halibut

1. In a stainless steel or glass bowl, combine garlic, olive oil, basil, salt, pepper, lemon juice, and parsley.
2. Place the halibut filets in a ziplock bag, and pour the marinade over the fish. Cover or seal and place in the refrigerator for 1 hour, turning occasionally.
3. Preheat an outdoor grill for high heat and lightly oil grate. Med-high on my grill....Set grate 4 inches from the heat.
4. Remove halibut filets from marinade and drain off the excess. Grill filets 5 minutes per side or until fish is done when easily flaked with a fork.