Thaw fish, if frozen. With a sharp knife, cut the fish into 1 inch pieces; set aside.
In a 3-quart saucepan cook green pepper, onion, and garlic in hot oil until tender but not brown. Add undrained tomatoes, wine, tomato paste, parsley, bay leaf, coriander, nutmeg, red pepper, and 1 cup water. Bring to a boil; reduce heat. Cover and simmer 20 minutes.
Add fish pieces, undrained oysters, crab meat (if canned, add it undrained), and lemon slices to tomato mixture. Return to boiling, reduce heat. Cover and simmer 5 to 7 minutes or until fish flakes easily when tested with a fork.
Remove bay leaf.
To serve, ladle the soup over the toast in individual serving bowls.