Gut and scale whole 3 to 5 lb bluefish. Season fish inside and out with salt, pepper, and lots of fresh lemon juice. Fill cavity with stuffing made of breadcrumbs, butter, onion, garlic, tomato, celery, and any other vegetables and ingredients you choose. Wrap tightly in foil. Cook on grill for 10 to 15 minutes per side or until fish flakes easily.