Heat pan over medium heat and add the olive oil and onion. Cook for 1 minute stirring occasionally. Next add the celery, garlic and oregano and sauté for 2 minutes. Pour in the white wine and stir well. Bring to a simmer and let reduce by half or so. Now add the tomatoes and clam juice and bring to a simmer. Simmer for about 15-20 minutes. Next add in the shrimp and fish pieces and cook until fish and shrimp is just cooked through. Serves 6-8 people with left overs.