Sautee onions and mushrooms with olive oil until cooked.
In a separate pan cook the halibut and shrimp, breaking up halibut into small flaky pieces until cooked. Drain the fish juices when done.
Add the onion and mushroom mixture to the halibut and shrimp. Also add the corn, diced tomatoes, parsley, garlic, crushed red pepper, and bread crumbs. Mix together and cook until mixture is no longer runny.
Halve the bell peppers and clean. Drop the peppers in to boiling water and boil for 2 minutes. Drain the peppers and place in a glass pan. Fill the peppers with the above mixture and top with shredded mozzarella.
Cook the peppers at 350 degrees for 15 minutes or until the cheese is melted and brown.